Androgen Receptor Antagonists: Compounds that bind to and inhibit the activation of ANDROGEN RECEPTORS.Receptors, Androgen: Proteins, generally found in the CYTOPLASM, that specifically bind ANDROGENS and mediate their cellular actions. The complex of the androgen and receptor migrates to the CELL NUCLEUS where it induces transcription of specific segments of DNA.Flutamide: An antiandrogen with about the same potency as cyproterone in rodent and canine species.Androgens: Compounds that interact with ANDROGEN RECEPTORS in target tissues to bring about the effects similar to those of TESTOSTERONE. Depending on the target tissues, androgenic effects can be on SEX DIFFERENTIATION; male reproductive organs, SPERMATOGENESIS; secondary male SEX CHARACTERISTICS; LIBIDO; development of muscle mass, strength, and power.Androgen Antagonists: Compounds which inhibit or antagonize the biosynthesis or actions of androgens.Tosyl CompoundsThiohydantoinsDihydrotestosterone: A potent androgenic metabolite of TESTOSTERONE. It is produced by the action of the enzyme 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE.AnilidesOrchiectomy: The surgical removal of one or both testicles.Testosterone: A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.Prostatic Neoplasms: Tumors or cancer of the PROSTATE.Nitriles: Organic compounds containing the -CN radical. The concept is distinguished from CYANIDES, which denotes inorganic salts of HYDROGEN CYANIDE.Metribolone: A synthetic non-aromatizable androgen and anabolic steroid. It binds strongly to the androgen receptor and has therefore also been used as an affinity label for this receptor in the prostate and in prostatic tumors.Estradiol: The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids.Testosterone Congeners: Steroidal compounds related to TESTOSTERONE, the major mammalian male sex hormone. Testosterone congeners include important testosterone precursors in the biosynthetic pathways, metabolites, derivatives, and synthetic steroids with androgenic activities.Interleukin 1 Receptor Antagonist Protein: A ligand that binds to but fails to activate the INTERLEUKIN 1 RECEPTOR. It plays an inhibitory role in the regulation of INFLAMMATION and FEVER. Several isoforms of the protein exist due to multiple ALTERNATIVE SPLICING of its mRNA.Androgen-Insensitivity Syndrome: A disorder of sexual development transmitted as an X-linked recessive trait. These patients have a karyotype of 46,XY with end-organ resistance to androgen due to mutations in the androgen receptor (RECEPTORS, ANDROGEN) gene. Severity of the defect in receptor quantity or quality correlates with their phenotypes. In these genetic males, the phenotypic spectrum ranges from those with normal female external genitalia, through those with genital ambiguity as in Reifenstein Syndrome, to that of a normal male with INFERTILITY.Neurokinin-1 Receptor Antagonists: Compounds that inhibit or block the activity of NEUROKININ-1 RECEPTORS.Prostate: A gland in males that surrounds the neck of the URINARY BLADDER and the URETHRA. It secretes a substance that liquefies coagulated semen. It is situated in the pelvic cavity behind the lower part of the PUBIC SYMPHYSIS, above the deep layer of the triangular ligament, and rests upon the RECTUM.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Purinergic P1 Receptor Antagonists: Compounds that bind to and block the stimulation of PURINERGIC P1 RECEPTORS.Histamine H2 Antagonists: Drugs that selectively bind to but do not activate histamine H2 receptors, thereby blocking the actions of histamine. Their clinically most important action is the inhibition of acid secretion in the treatment of gastrointestinal ulcers. Smooth muscle may also be affected. Some drugs in this class have strong effects in the central nervous system, but these actions are not well understood.Piperidines: A family of hexahydropyridines.Serotonin 5-HT3 Receptor Antagonists: Drugs that bind to but do not activate SEROTONIN 5-HT3 RECEPTORS, thereby blocking the actions of SEROTONIN or SEROTONIN 5-HT3 RECEPTOR AGONISTS.Neoplasms, Hormone-Dependent: Certain tumors that 1, arise in organs that are normally dependent on specific hormones and 2, are stimulated or caused to regress by manipulation of the endocrine environment.Hormone Antagonists: Chemical substances which inhibit the function of the endocrine glands, the biosynthesis of their secreted hormones, or the action of hormones upon their specific sites.Excitatory Amino Acid Antagonists: Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.Nandrolone: C18 steroid with androgenic and anabolic properties. It is generally prepared from alkyl ethers of ESTRADIOL to resemble TESTOSTERONE but less one carbon at the 19 position.Angiotensin Receptor Antagonists: Agents that antagonize ANGIOTENSIN RECEPTORS. Many drugs in this class specifically target the ANGIOTENSIN TYPE 1 RECEPTOR.Dopamine Antagonists: Drugs that bind to but do not activate DOPAMINE RECEPTORS, thereby blocking the actions of dopamine or exogenous agonists. Many drugs used in the treatment of psychotic disorders (ANTIPSYCHOTIC AGENTS) are dopamine antagonists, although their therapeutic effects may be due to long-term adjustments of the brain rather than to the acute effects of blocking dopamine receptors. Dopamine antagonists have been used for several other clinical purposes including as ANTIEMETICS, in the treatment of Tourette syndrome, and for hiccup. Dopamine receptor blockade is associated with NEUROLEPTIC MALIGNANT SYNDROME.Cell Line, Tumor: A cell line derived from cultured tumor cells.Serotonin 5-HT2 Receptor Antagonists: Drugs that bind to but do not activate SEROTONIN 5-HT2 RECEPTORS, thereby blocking the actions of SEROTONIN or SEROTONIN 5-HT2 RECEPTOR AGONISTS. Included under this heading are antagonists for one or more specific 5-HT2 receptor subtypes.Adenosine A2 Receptor Antagonists: Compounds that selectively bind to and block the activation of ADENOSINE A2 RECEPTORS.Adenosine A1 Receptor Antagonists: Compounds that bind to and block the stimulation of ADENOSINE A1 RECEPTORS.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Purinergic P2 Receptor Antagonists: Compounds that bind to and block the stimulation of PURINERGIC P2 RECEPTORS.Narcotic Antagonists: Agents inhibiting the effect of narcotics on the central nervous system.Histamine H1 Antagonists: Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.3-Oxo-5-alpha-Steroid 4-Dehydrogenase: An enzyme that catalyzes the reduction of TESTOSTERONE to 5-ALPHA DIHYDROTESTOSTERONE.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Trinucleotide Repeats: Microsatellite repeats consisting of three nucleotides dispersed in the euchromatic arms of chromosomes.Receptors, Endothelin: Cell surface proteins that bind ENDOTHELINS with high affinity and trigger intracellular changes which influence the behavior of cells.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Muscarinic Antagonists: Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.Feminization: Development of female secondary SEX CHARACTERISTICS in the MALE. It is due to the effects of estrogenic metabolites of precursors from endogenous or exogenous sources, such as ADRENAL GLANDS or therapeutic drugs.Cyproterone Acetate: An agent with anti-androgen and progestational properties. It shows competitive binding with dihydrotestosterone at androgen receptor sites.GABA-A Receptor Antagonists: Drugs that bind to but do not activate GABA-A RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-A RECEPTOR AGONISTS.Transcriptional Activation: Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.Histamine Antagonists: Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonists. Classical antihistaminics block the histamine H1 receptors only.Serotonin Antagonists: Drugs that bind to but do not activate serotonin receptors, thereby blocking the actions of serotonin or SEROTONIN RECEPTOR AGONISTS.Phenylthiohydantoin: Thiohydantoin benzene derivative.Nuclear Receptor Coactivators: Proteins that enhance gene expression when associated with ligand bound activated NUCLEAR RECEPTORS. The coactivators may act through an enzymatic process that affects the rate of transcription or the structure of chromatin. Alternatively nuclear receptor coactivators can function as adaptor proteins that bring nuclear receptors into close proximity with transcriptional complexes.GABA Antagonists: Drugs that bind to but do not activate GABA RECEPTORS, thereby blocking the actions of endogenous GAMMA-AMINOBUTYRIC ACID and GABA RECEPTOR AGONISTS.Prostate-Specific Antigen: A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Sialoglycoproteins: Glycoproteins which contain sialic acid as one of their carbohydrates. They are often found on or in the cell or tissue membranes and participate in a variety of biological activities.Leukotriene Antagonists: A class of drugs designed to prevent leukotriene synthesis or activity by blocking binding at the receptor level.Receptors, Steroid: Proteins found usually in the cytoplasm or nucleus that specifically bind steroid hormones and trigger changes influencing the behavior of cells. The steroid receptor-steroid hormone complex regulates the transcription of specific genes.Nuclear Receptor Coactivator 2: A transcription factor that partners with ligand bound GLUCOCORTICOID RECEPTORS and ESTROGEN RECEPTORS to stimulate GENETIC TRANSCRIPTION. It plays an important role in FERTILITY as well as in METABOLISM of LIPIDS.Receptor, Endothelin A: A subtype of endothelin receptor found predominantly in the VASCULAR SMOOTH MUSCLE. It has a high affinity for ENDOTHELIN-1 and ENDOTHELIN-2.Estrenes: Unsaturated derivatives of the ESTRANES with methyl groups at carbon-13, with no carbon at carbon-10, and with no more than one carbon at carbon-17. They must contain one or more double bonds.Receptors, Serotonin: Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.Receptors, N-Methyl-D-Aspartate: A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.Serotonin 5-HT1 Receptor Antagonists: Drugs that bind to but do not activate SEROTONIN 5-HT1 RECEPTORS, thereby blocking the actions of SEROTONIN 5-HT1 RECEPTOR AGONISTS. Included under this heading are antagonists for one or more of the specific 5-HT1 receptor subtypes.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Gene Expression Regulation, Neoplastic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in neoplastic tissue.Dizocilpine Maleate: A potent noncompetitive antagonist of the NMDA receptor (RECEPTORS, N-METHYL-D-ASPARTATE) used mainly as a research tool. The drug has been considered for the wide variety of neurodegenerative conditions or disorders in which NMDA receptors may play an important role. Its use has been primarily limited to animal and tissue experiments because of its psychotropic effects.Testis: The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Muscular Disorders, Atrophic: Disorders characterized by an abnormal reduction in muscle volume due to a decrease in the size or number of muscle fibers. Atrophy may result from diseases intrinsic to muscle tissue (e.g., MUSCULAR DYSTROPHY) or secondary to PERIPHERAL NERVOUS SYSTEM DISEASES that impair innervation to muscle tissue (e.g., MUSCULAR ATROPHY, SPINAL).Biphenyl CompoundsReceptors, Interleukin-1: Cell surface receptors that are specific for INTERLEUKIN-1. Included under this heading are signaling receptors, non-signaling receptors and accessory proteins required for receptor signaling. Signaling from interleukin-1 receptors occurs via interaction with SIGNAL TRANSDUCING ADAPTOR PROTEINS such as MYELOID DIFFERENTIATION FACTOR 88.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Castration: Surgical removal or artificial destruction of gonads.TetrazolesRadioligand Assay: Quantitative determination of receptor (binding) proteins in body fluids or tissue using radioactively labeled binding reagents (e.g., antibodies, intracellular receptors, plasma binders).Adrenergic alpha-1 Receptor Antagonists: Drugs that bind to and block the activation of ADRENERGIC ALPHA-1 RECEPTORS.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.Benzazepines: Compounds with BENZENE fused to AZEPINES.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Indoles: Benzopyrroles with the nitrogen at the number one carbon adjacent to the benzyl portion, in contrast to ISOINDOLES which have the nitrogen away from the six-membered ring.Androstenols: Unsaturated androstanes which are substituted with one or more hydroxyl groups in any position in the ring system.Androstane-3,17-diol: The unspecified form of the steroid, normally a major metabolite of TESTOSTERONE with androgenic activity. It has been implicated as a regulator of gonadotropin secretion.COS Cells: CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Receptors, Estrogen: Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important.Sulfonamides: A group of compounds that contain the structure SO2NH2.Nicotinic Antagonists: Drugs that bind to nicotinic cholinergic receptors (RECEPTORS, NICOTINIC) and block the actions of acetylcholine or cholinergic agonists. Nicotinic antagonists block synaptic transmission at autonomic ganglia, the skeletal neuromuscular junction, and at central nervous system nicotinic synapses.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Prostatic Neoplasms, Castration-Resistant: Tumors or cancer of the PROSTATE which can grow in the presence of low or residual amount of androgen hormones such as TESTOSTERONE.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Xanthines: Purine bases found in body tissues and fluids and in some plants.Genitalia, Male: The male reproductive organs. They are divided into the external organs (PENIS; SCROTUM;and URETHRA) and the internal organs (TESTIS; EPIDIDYMIS; VAS DEFERENS; SEMINAL VESICLES; EJACULATORY DUCTS; PROSTATE; and BULBOURETHRAL GLANDS).Pyridines: Compounds with a six membered aromatic ring containing NITROGEN. The saturated version is PIPERIDINES.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Serotonin Receptor Agonists: Endogenous compounds and drugs that bind to and activate SEROTONIN RECEPTORS. Many serotonin receptor agonists are used as ANTIDEPRESSANTS; ANXIOLYTICS; and in the treatment of MIGRAINE DISORDERS.Histamine H3 Antagonists: Drugs that selectively bind to but do not activate HISTAMINE H3 RECEPTORS. They have been used to correct SLEEP WAKE DISORDERS and MEMORY DISORDERS.Bulbo-Spinal Atrophy, X-Linked: An X-linked recessive form of spinal muscular atrophy. It is due to a mutation of the gene encoding the ANDROGEN RECEPTOR.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Adrenergic alpha-2 Receptor Antagonists: Drugs that bind to and block the activation of ADRENERGIC ALPHA-2 RECEPTORS.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Pyrazoles: Azoles of two nitrogens at the 1,2 positions, next to each other, in contrast with IMIDAZOLES in which they are at the 1,3 positions.Cholestenone 5 alpha-Reductase: An oxidoreductase that catalyzes the conversion of 3-oxo-delta4 steroids into their corresponding 5alpha form. It plays an important role in the conversion of TESTOSTERONE into DIHYDROTESTOSTERONE and PROGESTERONE into DIHYDROPROGESTERONE.Peptides, Cyclic: Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).Androgen-Binding Protein: Carrier proteins produced in the Sertoli cells of the testis, secreted into the seminiferous tubules, and transported via the efferent ducts to the epididymis. They participate in the transport of androgens. Androgen-binding protein has the same amino acid sequence as SEX HORMONE-BINDING GLOBULIN. They differ by their sites of synthesis and post-translational oligosaccharide modifications.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Prostatic Hyperplasia: Increase in constituent cells in the PROSTATE, leading to enlargement of the organ (hypertrophy) and adverse impact on the lower urinary tract function. This can be caused by increased rate of cell proliferation, reduced rate of cell death, or both.Behavior, Animal: The observable response an animal makes to any situation.Androstenedione: A delta-4 C19 steroid that is produced not only in the TESTIS, but also in the OVARY and the ADRENAL CORTEX. Depending on the tissue type, androstenedione can serve as a precursor to TESTOSTERONE as well as ESTRONE and ESTRADIOL.Estrogen Receptor beta: One of the ESTROGEN RECEPTORS that has greater affinity for ISOFLAVONES than ESTROGEN RECEPTOR ALPHA does. There is great sequence homology with ER alpha in the DNA-binding domain but not in the ligand binding and hinge domains.Losartan: An antagonist of ANGIOTENSIN TYPE 1 RECEPTOR with antihypertensive activity due to the reduced pressor effect of ANGIOTENSIN II.GABA-B Receptor Antagonists: Drugs that bind to but do not activate GABA-B RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-B RECEPTOR AGONISTS.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.5-alpha Reductase Inhibitors: Drugs that inhibit 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE. They are commonly used to reduce the production of DIHYDROTESTOSTERONE.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Receptors, Bradykinin: Cell surface receptors that bind BRADYKININ and related KININS with high affinity and trigger intracellular changes which influence the behavior of cells. The identified receptor types (B-1 and B-2, or BK-1 and BK-2) recognize endogenous KALLIDIN; t-kinins; and certain bradykinin fragments as well as bradykinin itself.Cimetidine: A histamine congener, it competitively inhibits HISTAMINE binding to HISTAMINE H2 RECEPTORS. Cimetidine has a range of pharmacological actions. It inhibits GASTRIC ACID secretion, as well as PEPSIN and GASTRIN output.Substance P: An eleven-amino acid neurotransmitter that appears in both the central and peripheral nervous systems. It is involved in transmission of PAIN, causes rapid contractions of the gastrointestinal smooth muscle, and modulates inflammatory and immune responses.Receptor, Endothelin B: A subtype of endothelin receptor found predominantly in the KIDNEY. It may play a role in reducing systemic ENDOTHELIN levels.Endothelin-1: A 21-amino acid peptide produced in a variety of tissues including endothelial and vascular smooth-muscle cells, neurons and astrocytes in the central nervous system, and endometrial cells. It acts as a modulator of vasomotor tone, cell proliferation, and hormone production. (N Eng J Med 1995;333(6):356-63)Adenosine A3 Receptor Antagonists: Compounds that selectively bind to and block the activation of ADENOSINE A3 RECEPTORS.Receptors, Neurokinin-1: A class of cell surface receptors for TACHYKININS with a preference for SUBSTANCE P. Neurokinin-1 (NK-1) receptors have been cloned and are members of the G protein coupled receptor superfamily. They are found on many cell types including central and peripheral neurons, smooth muscle cells, acinar cells, endothelial cells, fibroblasts, and immune cells.Azepines: Seven membered heterocyclic rings containing a NITROGEN atom.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Dehydroepiandrosterone: A major C19 steroid produced by the ADRENAL CORTEX. It is also produced in small quantities in the TESTIS and the OVARY. Dehydroepiandrosterone (DHEA) can be converted to TESTOSTERONE; ANDROSTENEDIONE; ESTRADIOL; and ESTRONE. Most of DHEA is sulfated (DEHYDROEPIANDROSTERONE SULFATE) before secretion.Serotonin: A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Purinergic P2X Receptor Antagonists: Compounds that bind to and block the stimulation of PURINERGIC P2X RECEPTORS. Included under this heading are antagonists for specific P2X receptor subtypes.Devazepide: A derivative of benzodiazepine that acts on the cholecystokinin A (CCKA) receptor to antagonize CCK-8's (SINCALIDE) physiological and behavioral effects, such as pancreatic stimulation and inhibition of feeding.Receptors, Cholecystokinin: Cell surface proteins that bind cholecystokinin (CCK) with high affinity and trigger intracellular changes influencing the behavior of cells. Cholecystokinin receptors are activated by GASTRIN as well as by CCK-4; CCK-8; and CCK-33. Activation of these receptors evokes secretion of AMYLASE by pancreatic acinar cells, acid and PEPSIN by stomach mucosal cells, and contraction of the PYLORUS and GALLBLADDER. The role of the widespread CCK receptors in the central nervous system is not well understood.Sertoli Cells: Supporting cells projecting inward from the basement membrane of SEMINIFEROUS TUBULES. They surround and nourish the developing male germ cells and secrete ANDROGEN-BINDING PROTEIN and hormones such as ANTI-MULLERIAN HORMONE. The tight junctions of Sertoli cells with the SPERMATOGONIA and SPERMATOCYTES provide a BLOOD-TESTIS BARRIER.Mice, Inbred C57BLReceptors, Vasopressin: Specific molecular sites or proteins on or in cells to which VASOPRESSINS bind or interact in order to modify the function of the cells. Two types of vasopressin receptor exist, the V1 receptor in the vascular smooth muscle and the V2 receptor in the kidneys. The V1 receptor can be subdivided into V1a and V1b (formerly V3) receptors.PyrrolidinesSteroid 17-alpha-Hydroxylase: A microsomal cytochrome P450 enzyme that catalyzes the 17-alpha-hydroxylation of progesterone or pregnenolone and subsequent cleavage of the residual two carbons at C17 in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP17 gene, generates precursors for glucocorticoid, androgen, and estrogen synthesis. Defects in CYP17 gene cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL) and abnormal sexual differentiation.Estrogen Receptor alpha: One of the ESTROGEN RECEPTORS that has marked affinity for ESTRADIOL. Its expression and function differs from, and in some ways opposes, ESTROGEN RECEPTOR BETA.Serotonin 5-HT4 Receptor Antagonists: Drugs that bind to but do not activate SEROTONIN 5-HT4 RECEPTORS, thereby blocking the actions of SEROTONIN or SEROTONIN RECEPTOR AGONISTS.2-Amino-5-phosphonovalerate: The D-enantiomer is a potent and specific antagonist of NMDA glutamate receptors (RECEPTORS, N-METHYL-D-ASPARTATE). The L form is inactive at NMDA receptors but may affect the AP4 (2-amino-4-phosphonobutyrate; APB) excitatory amino acid receptors.Ketanserin: A selective serotonin receptor antagonist with weak adrenergic receptor blocking properties. The drug is effective in lowering blood pressure in essential hypertension. It also inhibits platelet aggregation. It is well tolerated and is particularly effective in older patients.PiperazinesSteroids: A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)Benzimidazoles: Compounds with a BENZENE fused to IMIDAZOLES.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Estrogens: Compounds that interact with ESTROGEN RECEPTORS in target tissues to bring about the effects similar to those of ESTRADIOL. Estrogens stimulate the female reproductive organs, and the development of secondary female SEX CHARACTERISTICS. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds.QuinoxalinesReceptor, Cannabinoid, CB1: A subclass of cannabinoid receptor found primarily on central and peripheral NEURONS where it may play a role modulating NEUROTRANSMITTER release.Seminal Vesicles: A saclike, glandular diverticulum on each ductus deferens in male vertebrates. It is united with the excretory duct and serves for temporary storage of semen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Aromatase: An enzyme that catalyzes the desaturation (aromatization) of the ring A of C19 androgens and converts them to C18 estrogens. In this process, the 19-methyl is removed. This enzyme is membrane-bound, located in the endoplasmic reticulum of estrogen-producing cells of ovaries, placenta, testes, adipose, and brain tissues. Aromatase is encoded by the CYP19 gene, and functions in complex with NADPH-FERRIHEMOPROTEIN REDUCTASE in the cytochrome P-450 system.Hypospadias: A birth defect due to malformation of the URETHRA in which the urethral opening is below its normal location. In the male, the malformed urethra generally opens on the ventral surface of the PENIS or on the PERINEUM. In the female, the malformed urethral opening is in the VAGINA.Receptors, Thromboxane: Cell surface proteins that bind THROMBOXANES with high affinity and trigger intracellular changes influencing the behavior of cells. Some thromboxane receptors act via the inositol phosphate and diacylglycerol second messenger systems.QuinolinesNaltrexone: Derivative of noroxymorphone that is the N-cyclopropylmethyl congener of NALOXONE. It is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. The FDA has approved naltrexone for the treatment of alcohol dependence.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Sex Characteristics: Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.Famotidine: A competitive histamine H2-receptor antagonist. Its main pharmacodynamic effect is the inhibition of gastric secretion.Receptors, Dopamine D2: A subfamily of G-PROTEIN-COUPLED RECEPTORS that bind the neurotransmitter DOPAMINE and modulate its effects. D2-class receptor genes contain INTRONS, and the receptors inhibit ADENYLYL CYCLASES.Adrenergic alpha-Antagonists: Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.Receptors, Glucocorticoid: Cytoplasmic proteins that specifically bind glucocorticoids and mediate their cellular effects. The glucocorticoid receptor-glucocorticoid complex acts in the nucleus to induce transcription of DNA. Glucocorticoids were named for their actions on blood glucose concentration, but they have equally important effects on protein and fat metabolism. Cortisol is the most important example.Bradykinin: A nonapeptide messenger that is enzymatically produced from KALLIDIN in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from MAST CELLS during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter.Receptors, Neurokinin-2: A class of cell surface receptors for tachykinins that prefers neurokinin A; (NKA, substance K, neurokinin alpha, neuromedin L), neuropeptide K; (NPK); or neuropeptide gamma over other tachykinins. Neurokinin-2 (NK-2) receptors have been cloned and are similar to other G-protein coupled receptors.Estrogen Antagonists: Compounds which inhibit or antagonize the action or biosynthesis of estrogenic compounds.Cannabinoid Receptor Antagonists: Compounds that inhibit or block the activity of CANNABINOID RECEPTORS.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Sex Differentiation: The process in developing sex- or gender-specific tissue, organ, or function after SEX DETERMINATION PROCESSES have set the sex of the GONADS. Major areas of sex differentiation occur in the reproductive tract (GENITALIA) and the brain.Adenosine: A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.Injections, Intraventricular: Injections into the cerebral ventricles.Naloxone: A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.Anabolic Agents: These compounds stimulate anabolism and inhibit catabolism. They stimulate the development of muscle mass, strength, and power.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Mineralocorticoid Receptor Antagonists: Drugs that bind to and block the activation of MINERALOCORTICOID RECEPTORS by MINERALOCORTICOIDS such as ALDOSTERONE.Receptors, Progesterone: Specific proteins found in or on cells of progesterone target tissues that specifically combine with progesterone. The cytosol progesterone-receptor complex then associates with the nucleic acids to initiate protein synthesis. There are two kinds of progesterone receptors, A and B. Both are induced by estrogen and have short half-lives.Imidazoles: Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).QuinuclidinesAdrenergic Antagonists: Drugs that bind to but do not activate ADRENERGIC RECEPTORS. Adrenergic antagonists block the actions of the endogenous adrenergic transmitters EPINEPHRINE and NOREPINEPHRINE.Gonadal Steroid Hormones: Steroid hormones produced by the GONADS. They stimulate reproductive organs, germ cell maturation, and the secondary sex characteristics in the males and the females. The major sex steroid hormones include ESTRADIOL; PROGESTERONE; and TESTOSTERONE.BenzodiazepinonesFinasteride: An orally active 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE inhibitor. It is used as a surgical alternative for treatment of benign PROSTATIC HYPERPLASIA.Organ Size: The measurement of an organ in volume, mass, or heaviness.Adrenergic beta-2 Receptor Antagonists: Drugs that bind to and block the activation of ADRENERGIC BETA-2 RECEPTORS.Histamine: An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.Bicuculline: An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.Angiotensin II: An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.

Switch from antagonist to agonist of the androgen receptor bicalutamide is associated with prostate tumour progression in a new model system. (1/288)

Advanced prostate cancer is treated by androgen ablation and/or androgen receptor (AR) antagonists. In order to investigate the mechanisms relevant to the development of therapy-resistant tumours, we established a new tumour model which closely resembles the situation in patients who receive androgen ablation therapy. Androgen-sensitive LNCaP cells were kept in androgen-depleted medium for 87 passages. The new LNCaP cell subline established in this manner, LNCaP-abl, displayed a hypersensitive biphasic proliferative response to androgen until passage 75. Maximal proliferation of LNCaP-abl cells was achieved at 0.001 nM of the synthetic androgen methyltrienolone (R1881), whereas 0.01 nM of this compound induced the same effect in parental cells. At later passages (> 75), androgen exerted an inhibitory effect on growth of LNCaP-abl cells. The non-steroidal anti-androgen bicalutamide stimulated proliferation of LNCaP-abl cells. AR protein expression in LNCaP-abl cells increased approximately fourfold. The basal AR transcriptional activity was 30-fold higher in LNCaP-abl than in LNCaP cells. R1881 stimulated reporter gene activity in LNCaP-abl cells even at 0.01 nM, whereas 0.1 nM of R1881 was needed for induction of the same level of reporter gene activity in LNCaP cells. Bicalutamide that acts as a pure antagonist in parental LNCaP cells showed agonistic effects on AR transactivation activity in LNCaP-abl cells and was not able to block the effects of androgen in these cells. The non-steroidal AR blocker hydroxyflutamide exerted stimulatory effects on AR activity in both LNCaP and LNCaP-abl cells; however, the induction of reporter gene activity by hydroxyflutamide was 2.4- to 4-fold higher in the LNCaP-abl subline. The changes in AR activity were associated neither with a new alteration in AR cDNA sequence nor with amplification of the AR gene. Growth of LNCaP-abl xenografts in nude mice was stimulated by bicalutamide and repressed by testosterone. In conclusion, our results show for the first time that the nonsteroidal anti-androgen bicalutamide acquires agonistic properties during long-term androgen ablation. These findings may have repercussions on the natural course of prostate cancer with androgen deprivation and on strategies of therapeutic intervention.  (+info)

Inhibition of p160-mediated coactivation with increasing androgen receptor polyglutamine length. (2/288)

Normal polymorphic size variation of the exon 1 CAG microsatellite of the androgen receptor (AR) is associated with prostate cancer, benign prostatic hyperplasia and male infertility. Furthermore, abnormal expansion of the satellite leads to Kennedy's disease. We have shown recently that the AR N-terminal domain (NTD), which contains the polyglutamine (polyQ) stretch (encoded by the CAG repeat), functionally interacts with the C-termini of p160 coactivators. In the present study we explored possible AR CAG size effects on the p160 coactivator-mediated transactivation activity of the receptor. First, we mapped the p160 coactivator interaction on the AR NTD and found an interaction surface between amino acids 351 and 537. Although this region is 'downstream' from the polyQ stretch, it is still within the AR NTD, is implicated in constitutive transactivation activity of the receptor, and thus might be subject to polyQ size modulation. Indeed, cotrans- fection experiments in cultured prostate epithelial cells, using AR constructs of varying CAG sizes and p160 coactivator expression vectors, revealed that increased polyQ length, up to a size of 42 repeats, inhibited both basal and coactivator-mediated AR transactivation activity. AR expression in these cells, on the other hand, was unaffected by the same increased CAG repeat size range. We conclude that the AR NTD contributes to AR transactivation activity via functional interactions with p160 coactivators and that increasing polyQ length negatively affects p160-mediated coactivation of the AR. This molecular mechanism thus might explain, at least in part, the observed phenotypic effects of the AR CAG size polymorphism.  (+info)

Acute impairment of relaxation by low levels of testosterone in porcine coronary arteries. (3/288)

OBJECTIVES: While there are many suggested reasons for the marked gender bias in cardiovascular events, much of the available data indicate that circulating estrogens are cardioprotective. The possibility that endogenous androgens may be detrimental to the cardiovascular system has received relatively less attention. We investigated the short-term modulatory effects of various concentrations of testosterone on vascular function in isolated porcine coronary artery rings. RESULTS: The higher concentrations (> 1 microM) of testosterone relaxed U46619-contracted coronary artery rings in an endothelium-independent manner. This direct effect was insensitive to the testosterone receptor antagonists, flutamide and cyproterone acetate. Short-term exposure (20 min) to low levels of testosterone (1-100 nM), which were ineffective on their own on vascular function, significantly diminished relaxation to bradykinin and calcium ionophore A23187 but not those produced by levcromakalim and sodium nitroprusside. The inhibitory effect observed with 1 nM testosterone was only partially reversed by flutamide and cyproterone acetate and unaltered in the presence of actinomycin D and cycloheximide. CONCLUSIONS: These results demonstrate that acute treatment with testosterone, at concentrations that have no effect on their own, reduces vasorelaxation. Furthermore, they suggest that this modulatory action may be in part independent of the classical testosterone receptor since it was not completely sensitive to the anti-androgens and was not inhibited by the transcriptional and translational inhibitors. These findings support the postulation that testosterone may have unfavorable influences on vascular function.  (+info)

Differential effects of 17beta-estradiol and testosterone on the contractile responses of porcine coronary arteries. (4/288)

1. We investigated the effects of short-term exposure to physiological levels of 17beta-estradiol and testosterone on vasocontractile responses in porcine coronary artery rings. 2. Concentration-response curves to endothelin-1, 5-hydroxytryptamine, the thromboxane analogue U46619 and KCl were constructed in endothelium-intact and endothelium-disrupted artery rings. 3. Thirty minutes exposure to 17beta-estradiol (1 and 30 nM) significantly attenuated vasoconstriction to endothelin-1, 5-hydroxytryptamine and U46619. Conversely, the same concentrations of testosterone significantly potentiated responses elicited by these contractile agents. These inhibitory effects of 17beta-estradiol and enhancing actions of testosterone on contractions were endothelium-independent. KCl-mediated contractions were unaffected by the presence of either sex hormones. 4. The oestrogen receptor antagonists, tamoxifen (10 microM) and ICI 182,780 (10 microM), were unable to reverse the inhibitory influence 1 nM 17beta-estradiol had on the agonist-mediated contractile responses. Similarly, the androgen receptor antagonists, flutamide (10 microM) and cyproterone acetate (10 microM), failed to affect the potentiating activities of 1 nM testosterone. The alteration in vasoconstrictive responses observed following acute exposure to either 1 nM 17beta-estradiol and 1 nM testosterone were apparent even in the presence of the protein synthesis inhibitor cycloheximide (10 microM) and the transcription inhibitor actinomycin D (10 microM). 6. In conclusion, we report a unique type of sex hormone action on the coronary vasculature. These events occur at low nanomolar concentrations of 17beta-estradiol and testosterone, are insensitive to conventional sex hormone receptor antagonists, are not blocked by de novo protein synthesis inhibitors and have rapid time-courses that are uncharacteristic of classical genomic activities.  (+info)

Specific recognition of androgens by their nuclear receptor. A structure-function study. (5/288)

Androgens, like progestins, are 3-ketosteroids with structural differences restricted to the 17beta substituent in the steroid D-ring. To better understand the specific recognition of ligands by the human androgen receptor (hAR), a homology model of the ligand-binding domain (LBD) was constructed based on the progesterone receptor LBD crystal structure. Several mutants of residues potentially involved in the specific recognition of ligands in the hAR were constructed and tested for their ability to bind agonists. Their transactivation capacity in response to agonist (R1881) and antagonists (cyproterone acetate, hydroxyflutamide, and ICI 176344) was also measured. Substitution of His(874) by alanine, only marginally impairs the ligand-binding and transactivation capacity of the hAR receptor. In contrast, mutations of Thr(877) and, to a greater extent, Asn(705) perturb ligand recognition, alter transactivation efficiency, and broaden receptor specificity. Interestingly, the N705A mutant acquires progesterone receptor (PR) properties for agonist ligands but, unlike wild type AR and PR, loses the capacity to repress transactivation with nonsteroidal antagonists. Models of the hAR.LBD complexes with several ligands are presented, which suggests new directions for drug design.  (+info)

The RING finger protein SNURF modulates nuclear trafficking of the androgen receptor. (6/288)

The androgen receptor (AR) is a transcription factor that mediates androgen action. We have used the green fluorescent protein (GFP) technique to investigate dynamics of nuclear trafficking of human AR in living cells. In the absence of ligand, the GFP-AR fusion protein is distributed between cytoplasm and nuclei. Androgen exposure leads to a rapid and complete import of GFP-AR to nuclei of CV-1 cells (>=90% nuclear in 30 minutes), whereas a pure antiandrogen, Casodex, elicits a slower (<40% nuclear in 30 minutes) and incomplete transfer. Unliganded ARs with mutations in the basic amino acids of the bipartite nuclear localization signal (NLS) within the second zinc finger and the hinge region are predominantly cytoplasmic and their androgen-dependent nuclear import is severely compromised ((3/4)20% nuclear in 30 minutes). Interestingly, substitutions of the Leu residues flanking the bipartite NLS lead to inefficient nuclear transfer in response to androgen ((3/4)20% nuclear in 30 minutes). The ligand-binding domain of AR, which represses bipartite NLS activity, contains an agonist-specific NLS. The small nuclear RING finger protein SNURF, which interacts with AR through a region overlapping with the bipartite NLS, facilitates AR import to nuclei and retards its export on hormone withdrawal. More AR is associated with the nuclear matrix in the presence than absence of coexpressed SNURF. We suggest that the SNURF-mediated tethering of AR in nuclei represents a novel mechanism for activating steroid receptor functions.  (+info)

Antiandrogenic effects of novel androgen synthesis inhibitors on hormone-dependent prostate cancer. (7/288)

We have found that in addition to being potent inhibitors of 17alpha-hydroxylase/C17,20-lyase and/or 5alpha-reductase, some of our novel androgen synthesis inhibitors also interact with the mutated androgen receptor (AR) expressed in LNCaP prostate cancer cells and the wild-type AR expressed in hormone-dependent prostatic carcinomas. The effects of these compounds on the proliferation of hormone-dependent human prostatic cancer cells were determined in vitro and in vivo. L-2 and L-10 are delta4-3-one-pregnane derivatives. L-35 and L-37 are delta5-3beta-ol-androstane derivatives, and L-36 and L-39 are delta4-3-one-androstane-derived compounds. L-2, L-10, and L-36 (L-36 at low concentrations) stimulated the growth of LNCaP cells, indicating that they were interacting agonistically with the mutated AR expressed in LNCaP cells. L-35, L-37, and L-39 acted as LNCaP AR antagonists. To determine whether the growth modulatory effects of our novel compounds were specific for the mutated LNCaP AR, competitive binding studies were performed with LNCaP cells and PC-3 cells stably transfected with the wild-type AR (designated PC-3AR). Regardless of AR receptor type, all of our novel compounds were effective at preventing binding of the synthetic androgen methyl-trienolone[17alpha-methyl-(3H)-R1881 to both the LNCaP AR and the wildtype AR. L-36, L-37, and L-39 (5.0 microM) prevented binding by >90%, whereas L-35 inhibited binding by 30%. To determine whether the compounds were acting as agonists or antagonists, LNCaP cells and PC-3AR cells were transfected with the pMAMneoLUC reporter gene. When luciferase activity was induced by dihydrotestosterone, all of the compounds were found to be potent inhibitors of transcriptional activity, and the pattern of inhibition was similar for both receptor types. However, L-2, L-10, and L-36 were determined to be AR agonists, and L-35, L-37, and L-39 were wild-type AR antagonists. When tested in vivo, L-39 was the only AR antagonist that proved to be effective at inhibiting the growth of LNCaP prostate tumor growth. L-39 slowed tumor growth rate in LNCaP tumors grown in male SCID mice to the same level as orchidectomy, significantly reduced tumor weights (P < 0.05), significantly lowered serum levels of prostate-specific antigen (P < 0.02), and significanty lowered serum levels of testosterone (P < 0.05). L-39 also proved to be effective when tested against the PC-82 prostate cancer xenograft that expresses wild-type AR. These results show that some of our compounds initially developed to be inhibitors of androgen synthesis also interact with the human AR and modulate the proliferation of hormone-dependent prostatic cancer cells. Therefore, compounds such as L-39, which have multifunctional activities, hold promise for the treatment of androgen-dependent prostate tumors.  (+info)

Androgen receptor antagonism by the organophosphate insecticide fenitrothion. (8/288)

Organophosphate insecticides represent one of the most widely used classes of pesticides with high potential for human exposure in both rural and residential environments. We investigated the interaction of the organophosphothioate pesticide fenitrothion (O,O-dimethyl O-(4-nitro-m-tolyl) phosphorothioate) with the human androgen receptor (AR). Fenitrothion blocked dihydrotestosterone-dependent AR activity in a concentration-dependent and competitive manner in HepG2 human hepatoma liver cells transiently transfected with human AR and an AR-dependent luciferase reporter gene. Schild regression analysis yielded an equilibrium dissociation constant value of 2.18 x 10(-8) M. To determine the antiandrogenic potential of fenitrothion in vivo, 7-week-old castrated Sprague-Dawley rats were dosed once a day for 7 days with testosterone propionate (50 microg/day, sc) plus gavage doses of either corn oil vehicle or fenitrothion (15 or 30 mg/kg/day). An additional group of rats was given testosterone propionate and flutamide (50 mg/kg/day). Motor activity and acetylcholinesterase activity in whole blood and brain were also assessed. Both fenitrothion and the reference antiandrogen flutamide caused significant decreases in the ventral prostate, seminal vesicle, and levator ani plus bulbocavernosus muscles tissue weights. In contrast, blood acetylcholinesterase activity, a standard biomarker of organophosphate poisoning, was only inhibited at the higher dose of fenitrothion (30 mg/kg). Our results demonstrate that fenitrothion is a competitive AR antagonist, comparable in potency to the pharmaceutical antiandrogen flutamide and more potent, based on in vitro assays, than the known environmental antiandrogens linuron and p,p'-, 2,2-bis(p-hydroxyphenyl)-1,1-dichloroethylene ( p,p'-DDE).  (+info)

  • Investigations of structure-activity relationships surrounding this pharmacophore resulted in molecules with complete specificity for AR, antagonist activity on an AR mutant commonly observed in prostate cancer patients, and improved in vivo efficacy. (nih.gov)
  • Molecules based on this series of compounds have the potential to provide unique and effective clinical opportunities for treatment of prostate cancer and other androgen-dependent diseases. (nih.gov)
  • SAN FRANCISCO - Early use of the androgen receptor antagonist apalutamide for metastatic castration-sensitive prostate cancer has a sustained carry-over benefit regardless of subsequent therapy , an exploratory analysis of the TITAN trial suggests. (mdedge.com)
  • Coupled cistrome and transcriptome profiling upon small molecule antagonism led to the identification of a core set of AR direct effector genes that are most likely to mediate the activities of targeted agents: unbiased pathway mapping revealed that AR is a key modulator of steroid metabolism by forming a tightly controlled feedback loop with other nuclear receptor family members and this oncogenic effect can be relieved by antagonist treatment. (biomedcentral.com)
  • Here we investigated EPI-001, a small-molecule antagonist of AR NTD that inhibits protein-protein interactions necessary for AR transcriptional activity. (bcgsc.ca)
  • Cortexolone 17 alpha-propionate (CB-03-01, Clascoterone) is a topical and peripherally selective androgen antagonist, displays a strong local antiandrogenic activity in hamster's flank organ test, does not exhibit antiandrogenic activity after subcutaneous injection in vivo. (raystarbio.cn)
  • Topics presented in this meeting will include structure function relationships, the role of orphan receptors in development and metabolism, genome-wide analysis of receptor function, coactivators and corepressors, and drug discovery. (keystonesymposia.org)
  • be useful for the topical treatment of androgen-dependent skin disorders such as acne, androgenetic alopecia and hirsutism. (raystarbio.cn)
  • 1 2 Although there is a growing abundance of clinical and basic science data supporting a favorable effect of estrogen and perhaps progesterone on female cardiovascular risk and atherogenic processes, 3 4 5 6 there are comparatively few data on the possible proatherogenic effects of androgens. (ahajournals.org)
  • Castration, therefore, does not suppress adrenal androgens and achieves a "hormone-reduced" rather than a "hormone-free" state, hence, the recent renaming of this stage of the disease as castration-resistant in preference to hormone-refractory. (aacrjournals.org)
  • Glucocorticoids such as prednisone, exert a negative feedback mechanism on central stimulation of steroid production, thus preventing adrenal androgen production. (news-medical.net)