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)Seminal Vesicle Secretory Proteins: The secretory proteins of the seminal vesicles are proteins and enzymes that are important in the rapid clotting of the ejaculate. The major clotting protein is seminal vesicle-specific antigen. Many of these seminal vesicle proteins are under androgen regulation, and are substrates for the prostatic enzymes, such as the PROSTATE-SPECIFIC ANTIGEN, a protease and an esterase.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).Genital Neoplasms, Male: Tumor or cancer of the MALE GENITALIA.Synaptic Vesicles: Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.Prostatic Secretory Proteins: Proteins secreted by the prostate gland. The major secretory proteins from the human prostate gland include PROSTATE-SPECIFIC ANTIGEN, prostate-specific acid phosphatase, prostate-specific membrane antigen, and prostate-specific protein-94.Seminal Plasma Proteins: Proteins found in SEMEN. Major seminal plasma proteins are secretory proteins from the male sex accessory glands, such as the SEMINAL VESICLES and the PROSTATE. They include the seminal vesicle-specific antigen, an ejaculate clotting protein; and the PROSTATE-SPECIFIC ANTIGEN, a protease and an esterase.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.Hemospermia: Blood in the SEMEN, usually due to INFLAMMATION of the PROSTATE, the SEMINAL VESICLES, or both.Ejaculatory Ducts: Paired ducts in the human male through which semen is ejaculated into the urethra.Semen: The thick, yellowish-white, viscid fluid secretion of male reproductive organs discharged upon ejaculation. In addition to reproductive organ secretions, it contains SPERMATOZOA and their nutrient plasma.Transport Vesicles: Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.Cytoplasmic Vesicles: Membrane-limited structures derived from the plasma membrane or various intracellular membranes which function in storage, transport or metabolism.Secretory Vesicles: Vesicles derived from the GOLGI APPARATUS containing material to be released at the cell surface.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.Epididymis: The convoluted cordlike structure attached to the posterior of the TESTIS. Epididymis consists of the head (caput), the body (corpus), and the tail (cauda). A network of ducts leaving the testis joins into a common epididymal tubule proper which provides the transport, storage, and maturation of SPERMATOZOA.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.Castration: Surgical removal or artificial destruction of gonads.Organ Size: The measurement of an organ in volume, mass, or heaviness.Prostatectomy: Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic - removal through an incision above the pubis and through the urinary bladder; retropubic - as for suprapubic but without entering the urinary bladder; and transurethral (TRANSURETHRAL RESECTION OF PROSTATE).Prostatic Neoplasms: Tumors or cancer of the PROSTATE.Ejaculation: The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.Genital Diseases, Male: Pathological processes involving the male reproductive tract (GENITALIA, MALE).Calculi: An abnormal concretion occurring mostly in the urinary and biliary tracts, usually composed of mineral salts. Also called stones.Orchiectomy: The surgical removal of one or both testicles.Vas Deferens: The excretory duct of the testes that carries SPERMATOZOA. It rises from the SCROTUM and joins the SEMINAL VESICLES to form the ejaculatory duct.Bulbourethral Glands: Glands situated on each side of the prostate that secrete a fluid component of the seminal fluid into the urethra.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.Methyltestosterone: A synthetic hormone used for androgen replacement therapy and as an hormonal antineoplastic agent (ANTINEOPLASTIC AGENTS, HORMONAL).Sperm Transport: Passive or active movement of SPERMATOZOA from the testicular SEMINIFEROUS TUBULES through the male reproductive tract as well as within the female reproductive tract.Wolffian Ducts: A pair of excretory ducts of the middle kidneys (MESONEPHROI) of an embryo, also called mesonephric ducts. In higher vertebrates, Wolffian ducts persist in the male forming VAS DEFERENS, but atrophy into vestigial structures in the female.Sexual Maturation: Achievement of full sexual capacity in animals and in humans.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.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.COP-Coated Vesicles: TRANSPORT VESICLES formed when cell-membrane coated pits (COATED PITS, CELL-MEMBRANE) invaginate and pinch off. The outer surface of these vesicles is covered with a lattice-like network of COP (coat protein complex) proteins, either COPI or COPII. COPI coated vesicles transport backwards from the cisternae of the GOLGI APPARATUS to the rough endoplasmic reticulum (ENDOPLASMIC RETICULUM, ROUGH), while COPII coated vesicles transport forward from the rough endoplasmic reticulum to the Golgi apparatus.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Epithelium: One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Sperm Motility: Movement characteristics of SPERMATOZOA in a fresh specimen. It is measured as the percentage of sperms that are moving, and as the percentage of sperms with productive flagellar motion such as rapid, linear, and forward progression.Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Sperm Count: A count of SPERM in the ejaculum, expressed as number per milliliter.Liposomes: Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.Exocytosis: Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.Cysts: Any fluid-filled closed cavity or sac that is lined by an EPITHELIUM. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues.Testosterone Propionate: An ester of TESTOSTERONE with a propionate substitution at the 17-beta position.Tuberculosis, Male Genital: MYCOBACTERIUM infections of the male reproductive tract (GENITALIA, MALE).Flutamide: An antiandrogen with about the same potency as cyproterone in rodent and canine species.Golgi Apparatus: A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Androgen Antagonists: Compounds which inhibit or antagonize the biosynthesis or actions of androgens.Clathrin-Coated Vesicles: Vesicles formed when cell-membrane coated pits (COATED PITS, CELL-MEMBRANE) invaginate and pinch off. The outer surface of these vesicles is covered with a lattice-like network of the protein CLATHRIN. Shortly after formation, however, the clathrin coat is removed and the vesicles are referred to as ENDOSOMES.Cyproterone: An anti-androgen that, in the form of its acetate (CYPROTERONE ACETATE), also has progestational properties. It is used in the treatment of hypersexuality in males, as a palliative in prostatic carcinoma, and, in combination with estrogen, for the therapy of severe acne and hirsutism in females.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, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.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.