Endocrine Disruptors: Exogenous agents, synthetic and naturally occurring, which are capable of disrupting the functions of the ENDOCRINE SYSTEM including the maintenance of HOMEOSTASIS and the regulation of developmental processes. Endocrine disruptors are compounds that can mimic HORMONES, or enhance or block the binding of hormones to their receptors, or otherwise lead to activating or inhibiting the endocrine signaling pathways and hormone metabolism.Endocrine System: The system of glands that release their secretions (hormones) directly into the circulatory system. In addition to the ENDOCRINE GLANDS, included are the CHROMAFFIN SYSTEM and the NEUROSECRETORY SYSTEMS.Endocrine Glands: Ductless glands that secrete HORMONES directly into the BLOOD CIRCULATION. These hormones influence the METABOLISM and other functions of cells in the body.Benzhydryl Compounds: Compounds which contain the methyl radical substituted with two benzene rings. Permitted are any substituents, but ring fusion to any of the benzene rings is not allowed.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Environmental Pollutants: Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.Estrogens, Non-Steroidal: Non-steroidal compounds with estrogenic activity.United States Environmental Protection Agency: An agency in the Executive Branch of the Federal Government. It was created as an independent regulatory agency responsible for the implementation of federal laws designed to protect the environment. Its mission is to protect human health and the ENVIRONMENT.Methoxychlor: An insecticide. Methoxychlor has estrogenic effects in mammals, among other effects.Endocrine System Diseases: Pathological processes of the ENDOCRINE GLANDS, and diseases resulting from abnormal level of available HORMONES.Food Packaging: Containers, packaging, and packaging materials for processed and raw foods and beverages. It includes packaging intended to be used for storage and also used for preparation of foods such as microwave food containers versus COOKING AND EATING UTENSILS. Packaging materials may be intended for food contact or designated non-contact, for example, shipping containers. FOOD LABELING is also available.Diethylhexyl Phthalate: An ester of phthalic acid. It appears as a light-colored, odorless liquid and is used as a plasticizer for many resins and elastomers.Diethylstilbestrol: A synthetic nonsteroidal estrogen used in the treatment of menopausal and postmenopausal disorders. It was also used formerly as a growth promoter in animals. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), diethylstilbestrol has been listed as a known carcinogen. (Merck, 11th ed)Toxicity Tests: An array of tests used to determine the toxicity of a substance to living systems. These include tests on clinical drugs, foods, and environmental pollutants.Environmental Exposure: The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.Xenobiotics: Chemical substances that are foreign to the biological system. They include naturally occurring compounds, drugs, environmental agents, carcinogens, insecticides, etc.Phthalic Acids: A group of compounds that has the general structure of a dicarboxylic acid-substituted benzene ring. The ortho-isomer is used in dye manufacture. (Dorland, 28th ed)CarbanilidesEndocrine Gland Neoplasms: Tumors or cancer of the ENDOCRINE GLANDS.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.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.Atrazine: A selective triazine herbicide. Inhalation hazard is low and there are no apparent skin manifestations or other toxicity in humans. Acutely poisoned sheep and cattle may show muscular spasms, fasciculations, stiff gait, increased respiratory rates, adrenal degeneration, and congestion of the lungs, liver, and kidneys. (From The Merck Index, 11th ed)Chlordan: A highly poisonous organochlorine insecticide. The EPA has cancelled registrations of pesticides containing this compound with the exception of its use through subsurface ground insertion for termite control and the dipping of roots or tops of non-food plants. (From Merck Index, 11th ed)Plasticizers: Materials incorporated mechanically in plastics (usually PVC) to increase flexibility, workability or distensibility; due to the non-chemical inclusion, plasticizers leach out from the plastic and are found in body fluids and the general environment.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Prenatal Exposure Delayed Effects: The consequences of exposing the FETUS in utero to certain factors, such as NUTRITION PHYSIOLOGICAL PHENOMENA; PHYSIOLOGICAL STRESS; DRUGS; RADIATION; and other physical or chemical factors. These consequences are observed later in the offspring after BIRTH.Polychlorinated Biphenyls: Industrial products consisting of a mixture of chlorinated biphenyl congeners and isomers. These compounds are highly lipophilic and tend to accumulate in fat stores of animals. Many of these compounds are considered toxic and potential environmental pollutants.Oxazoles: Five-membered heterocyclic ring structures containing an oxygen in the 1-position and a nitrogen in the 3-position, in distinction from ISOXAZOLES where they are at the 1,2 positions.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.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Maternal Exposure: Exposure of the female parent, human or animal, to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals that may affect offspring. It includes pre-conception maternal exposure.Dichlorodiphenyl Dichloroethylene: An organochlorine pesticide, it is the ethylene metabolite of DDT.Hydrocarbons, Chlorinated: Hydrocarbon compounds with one or more of the hydrogens replaced by CHLORINE.Dibutyl Phthalate: A plasticizer used in most plastics and found in water, air, soil, plants and animals. It may have some adverse effects with long-term exposure.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.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.Polybrominated Biphenyls: Biphenyl compounds which are extensively brominated. Many of these compounds are toxic environmental pollutants.Trialkyltin Compounds: Organometallic compounds which contain tin and three alkyl groups.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Cryptorchidism: A developmental defect in which a TESTIS or both TESTES failed to descend from high in the ABDOMEN to the bottom of the SCROTUM. Testicular descent is essential to normal SPERMATOGENESIS which requires temperature lower than the BODY TEMPERATURE. Cryptorchidism can be subclassified by the location of the maldescended testis.Pesticides: Chemicals used to destroy pests of any sort. The concept includes fungicides (FUNGICIDES, INDUSTRIAL); INSECTICIDES; RODENTICIDES; etc.Parabens: Methyl, propyl, butyl, and ethyl esters of p-hydroxybenzoic acid. They have been approved by the FDA as antimicrobial agents for foods and pharmaceuticals. (From Hawley's Condensed Chemical Dictionary, 11th ed, p872)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.Genitalia, Female: The female reproductive organs. The external organs include the VULVA; BARTHOLIN'S GLANDS; and CLITORIS. The internal organs include the VAGINA; UTERUS; OVARY; and FALLOPIAN TUBES.Cosmetics: Substances intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions. Included in this definition are skin creams, lotions, perfumes, lipsticks, fingernail polishes, eye and facial makeup preparations, permanent waves, hair colors, toothpastes, and deodorants, as well as any material intended for use as a component of a cosmetic product. (U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Office of Cosmetics Fact Sheet (web page) Feb 1995)Phytoestrogens: PLANT EXTRACTS and compounds, primarily ISOFLAVONES, that mimic or modulate endogenous estrogens, usually by binding to ESTROGEN RECEPTORS.Androgen Antagonists: Compounds which inhibit or antagonize the biosynthesis or actions of androgens.Chlordecone: A highly chlorinated polycyclic hydrocarbon insecticide whose large number of chlorine atoms makes it resistant to degradation. It has been shown to be toxic to mammals and causes abnormal cellular changes in laboratory animals.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.Lindane: An organochlorine insecticide that has been used as a pediculicide and a scabicide. It has been shown to cause cancer.Insecticides: Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.DDT: A polychlorinated pesticide that is resistant to destruction by light and oxidation. Its unusual stability has resulted in difficulties in residue removal from water, soil, and foodstuffs. This substance may reasonably be anticipated to be a carcinogen: Fourth Annual Report on Carcinogens (NTP-85-002, 1985). (From Merck Index, 11th ed)Halogenated Diphenyl Ethers: Compounds that contain two halogenated benzene rings linked via an OXYGEN atom. Many polybrominated diphenyl ethers are used as FLAME RETARDANTS.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.Animal Use Alternatives: Alternatives to the use of animals in research, testing, and education. The alternatives may include reduction in the number of animals used, replacement of animals with a non-animal model or with animals of a species lower phylogenetically, or refinement of methods to minimize pain and distress of animals used.Flame Retardants: Materials applied to fabrics, bedding, furniture, plastics, etc. to retard their burning; many may leach out and cause allergies or other harm.Urogenital System: All the organs involved in reproduction and the formation and release of URINE. It includes the kidneys, ureters, BLADDER; URETHRA, and the organs of reproduction - ovaries, UTERUS; FALLOPIAN TUBES; VAGINA; and CLITORIS in women and the testes; SEMINAL VESICLES; PROSTATE; seminal ducts; and PENIS in men.Tetrachlorodibenzodioxin: A chemical by-product that results from burning or incinerating chlorinated industrial chemicals and other hydrocarbons. This compound is considered an environmental toxin, and may pose reproductive, as well as, other health risks for animals and humans.Phenyl Ethers: Ethers that are linked to a benzene ring structure.Biological Assay: A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Hazardous Substances: Elements, compounds, mixtures, or solutions that are considered severely harmful to human health and the environment. They include substances that are toxic, corrosive, flammable, or explosive.Hormones: Chemical substances having a specific regulatory effect on the activity of a certain organ or organs. The term was originally applied to substances secreted by various ENDOCRINE GLANDS and transported in the bloodstream to the target organs. It is sometimes extended to include those substances that are not produced by the endocrine glands but that have similar effects.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.Zearalenone: (S-(E))-3,4,5,6,8,10-Hexahydro-14,16-dihydroxy-3-methyl-1H-2-benzoxacyclotetradecin-1,7(8H)-dione. One of a group of compounds known under the general designation of resorcylic acid lactones. Cis, trans, dextro and levo forms have been isolated from the fungus Gibberella zeae (formerly Fusarium graminearum). They have estrogenic activity, cause toxicity in livestock as feed contaminant, and have been used as anabolic or estrogen substitutes.Multiple Endocrine Neoplasia Type 1: A form of multiple endocrine neoplasia that is characterized by the combined occurrence of tumors in the PARATHYROID GLANDS, the PITUITARY GLAND, and the PANCREATIC ISLETS. The resulting clinical signs include HYPERPARATHYROIDISM; HYPERCALCEMIA; HYPERPROLACTINEMIA; CUSHING DISEASE; GASTRINOMA; and ZOLLINGER-ELLISON SYNDROME. This disease is due to loss-of-function of the MEN1 gene, a tumor suppressor gene (GENES, TUMOR SUPPRESSOR) on CHROMOSOME 11 (Locus: 11q13).Calbindins: Calcium-binding proteins that are found in DISTAL KIDNEY TUBULES, INTESTINES, BRAIN, and other tissues where they bind, buffer and transport cytoplasmic calcium. Calbindins possess a variable number of EF-HAND MOTIFS which contain calcium-binding sites. Some isoforms are regulated by VITAMIN D.Toxicology: The science concerned with the detection, chemical composition, and biological action of toxic substances or poisons and the treatment and prevention of toxic manifestations.Environmental Remediation: Removal of ENVIRONMENTAL POLLUTANTS or contaminants for the general protection of the environment. This is accomplished by various chemical, biological, and bulk movement methods, in conjunction with ENVIRONMENTAL MONITORING.Dioxins: Chlorinated hydrocarbons containing heteroatoms that are present as contaminants of herbicides. Dioxins are carcinogenic, teratogenic, and mutagenic. They have been banned from use by the FDA.Environmental Health: The science of controlling or modifying those conditions, influences, or forces surrounding man which relate to promoting, establishing, and maintaining health.Epigenesis, Genetic: A genetic process by which the adult organism is realized via mechanisms that lead to the restriction in the possible fates of cells, eventually leading to their differentiated state. Mechanisms involved cause heritable changes to cells without changes to DNA sequence such as DNA METHYLATION; HISTONE modification; DNA REPLICATION TIMING; NUCLEOSOME positioning; and heterochromatization which result in selective gene expression or repression.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.Multiple Endocrine Neoplasia: A group of autosomal dominant diseases characterized by the combined occurrence of tumors involving two or more ENDOCRINE GLANDS that secrete PEPTIDE HORMONES or AMINES. These neoplasias are often benign but can be malignant. They are classified by the endocrine glands involved and the degree of aggressiveness. The two major forms are MEN1 and MEN2 with gene mutations on CHROMOSOME 11 and CHROMOSOME 10, respectively.Neurosecretory Systems: A system of NEURONS that has the specialized function to produce and secrete HORMONES, and that constitutes, in whole or in part, an ENDOCRINE SYSTEM or organ.Spermatogenesis: The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA.Ovary: The reproductive organ (GONADS) in female animals. In vertebrates, the ovary contains two functional parts: the OVARIAN FOLLICLE for the production of female germ cells (OOGENESIS); and the endocrine cells (GRANULOSA CELLS; THECA CELLS; and LUTEAL CELLS) for the production of ESTROGENS and PROGESTERONE.Thyroid Hormones: Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs.Polyethylene Terephthalates: Polyester polymers formed from terephthalic acid or its esters and ethylene glycol. They can be formed into tapes, films or pulled into fibers that are pressed into meshes or woven into fabrics.Uterus: The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.S100 Calcium Binding Protein G: A calbindin protein found in many mammalian tissues, including the UTERUS, PLACENTA, BONE, PITUITARY GLAND, and KIDNEYS. In intestinal ENTEROCYTES it mediates intracellular calcium transport from apical to basolateral membranes via calcium binding at two EF-HAND MOTIFS. Expression is regulated in some tissues by VITAMIN D.Organ Size: The measurement of an organ in volume, mass, or heaviness.Flutamide: An antiandrogen with about the same potency as cyproterone in rodent and canine species.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.Herbicides: Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE.Ethinyl Estradiol: A semisynthetic alkylated ESTRADIOL with a 17-alpha-ethinyl substitution. It has high estrogenic potency when administered orally, and is often used as the estrogenic component in ORAL CONTRACEPTIVES.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.Isoflavones: 3-Phenylchromones. Isomeric form of FLAVONOIDS in which the benzene group is attached to the 3 position of the benzopyran ring instead of the 2 position.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.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.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).Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Maternal-Fetal Exchange: Exchange of substances between the maternal blood and the fetal blood at the PLACENTA via PLACENTAL CIRCULATION. The placental barrier excludes microbial or viral transmission.Steroids: 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)Sperm Count: A count of SPERM in the ejaculum, expressed as number per milliliter.Sexual Maturation: Achievement of full sexual capacity in animals and in humans.Infertility, Male: The inability of the male to effect FERTILIZATION of an OVUM after a specified period of unprotected intercourse. Male sterility is permanent infertility.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.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.Genistein: An isoflavonoid derived from soy products. It inhibits PROTEIN-TYROSINE KINASE and topoisomerase-II (DNA TOPOISOMERASES, TYPE II); activity and is used as an antineoplastic and antitumor agent. Experimentally, it has been shown to induce G2 PHASE arrest in human and murine cell lines and inhibits PROTEIN-TYROSINE KINASE.Multiple Endocrine Neoplasia Type 2a: A form of multiple endocrine neoplasia characterized by the presence of medullary carcinoma (CARCINOMA, MEDULLARY) of the THYROID GLAND, and usually with the co-occurrence of PHEOCHROMOCYTOMA, producing CALCITONIN and ADRENALINE, respectively. Less frequently, it can occur with hyperplasia or adenoma of the PARATHYROID GLANDS. This disease is due to gain-of-function mutations of the MEN2 gene on CHROMOSOME 10 (Locus: 10q11.2), also known as the RET proto-oncogene that encodes a RECEPTOR PROTEIN-TYROSINE KINASE. It is an autosomal dominant inherited disease.Food Contamination: The presence in food of harmful, unpalatable, or otherwise objectionable foreign substances, e.g. chemicals, microorganisms or diluents, before, during, or after processing or storage.Puberty: A period in the human life in which the development of the hypothalamic-pituitary-gonadal system takes place and reaches full maturity. The onset of synchronized endocrine events in puberty lead to the capacity for reproduction (FERTILITY), development of secondary SEX CHARACTERISTICS, and other changes seen in ADOLESCENT DEVELOPMENT.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Thyroid Gland: A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively.Breast Neoplasms: Tumors or cancer of the human BREAST.Animals, Newborn: Refers to animals in the period of time just after birth.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Models, Animal: Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.Testicular Neoplasms: Tumors or cancer of the TESTIS. Germ cell tumors (GERMINOMA) of the testis constitute 95% of all testicular neoplasms.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Receptors, Aryl Hydrocarbon: Cytoplasmic proteins that bind certain aryl hydrocarbons, translocate to the nucleus, and activate transcription of particular DNA segments. AH receptors are identified by their high-affinity binding to several carcinogenic or teratogenic environmental chemicals including polycyclic aromatic hydrocarbons found in cigarette smoke and smog, heterocyclic amines found in cooked foods, and halogenated hydrocarbons including dioxins and polychlorinated biphenyls. No endogenous ligand has been identified, but an unknown natural messenger with a role in cell differentiation and development is suspected.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.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.Enteroendocrine Cells: Cells found throughout the lining of the GASTROINTESTINAL TRACT that contain and secrete regulatory PEPTIDE HORMONES and/or BIOGENIC AMINES.Pancreas: A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Multiple Endocrine Neoplasia Type 2b: Similar to MEN2A, it is also caused by mutations of the MEN2 gene, also known as the RET proto-oncogene. Its clinical symptoms include medullary carcinoma (CARCINOMA, MEDULLARY) of THYROID GLAND and PHEOCHROMOCYTOMA of ADRENAL MEDULLA (50%). Unlike MEN2a, MEN2b does not involve PARATHYROID NEOPLASMS. It can be distinguished from MEN2A by its neural abnormalities such as mucosal NEUROMAS on EYELIDS; LIP; and TONGUE, and ganglioneuromatosis of GASTROINTESTINAL TRACT leading to MEGACOLON. It is an autosomal dominant inherited disease.United StatesIslets of Langerhans: Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.Genes, Reporter: Genes whose expression is easily detectable and therefore used to study promoter activity at many positions in a target genome. In recombinant DNA technology, these genes may be attached to a promoter region of interest.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.Luciferases: Enzymes that oxidize certain LUMINESCENT AGENTS to emit light (PHYSICAL LUMINESCENCE). The luciferases from different organisms have evolved differently so have different structures and substrates.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Antineoplastic Agents, Hormonal: Antineoplastic agents that are used to treat hormone-sensitive tumors. Hormone-sensitive tumors may be hormone-dependent, hormone-responsive, or both. A hormone-dependent tumor regresses on removal of the hormonal stimulus, by surgery or pharmacological block. Hormone-responsive tumors may regress when pharmacologic amounts of hormones are administered regardless of whether previous signs of hormone sensitivity were observed. The major hormone-responsive cancers include carcinomas of the breast, prostate, and endometrium; lymphomas; and certain leukemias. (From AMA Drug Evaluations Annual 1994, p2079)Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Linuron: A selective pre- and post-emergence herbicide. (From Merck Index, 11th ed)Research Design: A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly.DNA Methylation: Addition of methyl groups to DNA. DNA methyltransferases (DNA methylases) perform this reaction using S-ADENOSYLMETHIONINE as the methyl group donor.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.