Androgen regulation of specific mRNAs, endoplasmic reticulum and Golgi-system

Revisiting The Relationship between The Ejaculatory Abstinence Period and Semen Characteristics

Variation in the ejaculatory abstinence period suggested by different guidance bodies have resulted in a growing concern among researchers and clinicians over what the precise period of ejaculatory abstinence ought to be for an optimal semen sample. Several studies have thus been undertaken to examine the association between the length of sexual abstinence and semen characteristics. Not all studies, however, have arrived at the same conclusions. This study aims to review all existing literature published during the past few decades pertaining to the influence of ejaculatory abstinence on semen quality. For the purpose of this systematic review, all data related to sexual abstinence duration and seminal parameters were re-analysed to homogenize the current data. Thorough PubMed, MEDLINE and Google Scholar, a literature search was conducted using the keywords "sexual abstinence", "ejaculatory abstinence", "semen", "spermatozoa", "semen analysis", "sperm parameters", "motility", "reactive oxygen species (ROS)" and "DNA fragmentation". After carefully reviewing all the literature, 30 relevant papers, both written in English and published between January 1979 and December 2016, were included in this review. The weight of the evidence suggests that the decline in semen volume and sperm concentration with shorter abstinence periods is accompanied by a substantial improvement in sperm motility characteristics, especially progressive motility and velocity. Nevertheless, available data are insufficient to support definitive conclusions regarding the influence of the ejaculatory abstinence period on advanced semen parameters (ROS, DNA fragmentation and seminal plasma antioxidant capacity) and pregnancy rates. In conclusion, taking all data into account, shortening of the abstinence period may be beneficial to sperm quality. Furthermore, we recommend that the current guidelines regarding the prescribed abstinence period should be revisited.

The effect of chronic kisspeptin administration on seminal fructose levels in male mice

The discovery that kisspeptin was critical for normal fertility in all mammalian species including humans, ushered in a new chapter in our understanding of the control of GnRH secretion. Kisspeptin, the product of the KISS1 gene, plays an essential role in the regulation of spermatogenesis acting primarily at the hypothalamic level of the gonadotropic axis. Among the many identified substances in human semen, fructose is becoming increasingly significant. Fructose is synthesized and secreted by the seminal vesicles. Its synthesis is regulated by androgens and it is correlated directly with the levels of testosterone. Dose dependent degeneration of seminal vesicle has been described following intraperitoneal kisspeptin treatment; however, effects of kisspeptin administration on the levels of seminal fructose remain elusive till date. The present study, therefore, addresses the effects of 12-day administration of kisspeptin on seminal fructose levels in male mice. Kisspeptin-10 was administered intraperitoneally at different dosage concentrations (1 μg, 1 ng, and 10 ρg) to adult male mice, twice daily for 12 days. Seminal fructose levels were studied photometrically after 12 days of treatment. At the end of the treatment, seminal fructose levels decreased significantly after all tested doses. Chronic intermittent kisspeptin-10 administration negatively regulates seminal fructose levels in adult male mice.

Distribution of androgen and oestrogen receptors-α in the seminal vesicle-related spinal neurones in male rats

The seminal vesicles are male accessory sex glands that contribute much of the seminal fluid volume. Previous studies have suggested that the majority of autonomic innervations to the rat seminal vesicles originate from the bilateral major pelvic ganglia. Many preganglionic autonomic neurones innervating the pelvic ganglion were expressed androgen receptors (AR) or oestrogen receptor (ER)-α immunoreactivity. However, direct neuroanatomic data regarding the distribution of AR and ER-α in seminal vesicle related-spinal neurones are lacking. In the present study, a nonvirulent pseudorabies virus (PRV-152 strain) was used in a retrograde tracing experiment. Four days after PRV injection into the seminal vesicles of male rats, spinal cord sections were prepared. Double- and triple-fluorescence techniques using AR and ER-α with choline acetyltransferase (ChAT) and PRV were used to investigate the AR and ER-α distribution in the seminal vesicles related spinal neurones in male rats. In lamina X, 14% of the PRV-labelled neurones in the L1-L4 segments and 43% in the L5-S1 segments were double-labelled with AR. In the L1-L4 segments, 6% of PRV-labelled neurones and 26% in the L5-S1 segments were double-labelled with ER-α. In the intermedial cell column area, 10% of PRV-labelled neurones in the L1-L4 segments and 47% of PRV-labelled neurones in the L5-S1 segments were double-labelled with AR. Up to 16% of PRV-labelled neurones in the L5-S1 segments were double-labelled with ER-α. No PRV-labelled neurones in the L1-L4 segments were double-labelled with ER-α. However, for the AR and ER-α/PRV/ChAT triple-fluorescence experiments, very few seminal vesicle preganglionic neurones expressed AR or ER-α. Our data suggests that many spinal interneurones but not preganglionic neurones involved in the seminal vesicle control in male rats were double-labelled with AR or ER-α, and they were mainly located at the parasympathetic level in the spinal cord.

Evaluation of the effects of testosterone and luteinizing hormone on regulation of β-amyloid in male 3xTg-AD mice

During normal aging, men experience a significant decline in testosterone levels and a compensatory elevation in levels of gonadotropin luteinizing hormone (LH). Both low testosterone and elevated LH have been identified as significant risk factors for the development of Alzheimer's disease (AD) in men. It is unclear whether changes in testosterone or LH primarily underlie the relationship with AD, and therefore may be a more suitable therapeutic target. To examine this issue, we compared levels of β-amyloid (Aβ) immunoreactivity in male 3xTg-AD mice under varying experimental conditions associated with relatively low or high levels of testosterone and/or LH. In gonadally intact mice, Aβ accumulation increased after treatment with the gonadotropin-releasing hormone agonist leuprolide, which inhibits the hypothalamic-pituitary-gonadal (HPG) axis and reduces both testosterone and LH levels. In gonadectomized (GDX) mice with low testosterone and high LH, we also observed increased Aβ levels. Treatment of GDX mice with testosterone significantly reduced Aβ levels. In contrast, leuprolide did not significantly decrease Aβ levels and moreover, inhibited the Aβ-lowering effect of testosterone. Evaluation of hippocampal-dependent behavior revealed parallel findings, with performance in GDX mice improved by testosterone but not leuprolide. These data suggest that Aβ-lowering actions of testosterone are mediated directly by androgen pathways rather than indirectly via regulation of LH and the HPG axis. These findings support the clinical evaluation of androgen therapy in the prevention and perhaps treatment of AD in hypogonadal men.

Androgen-dependent synthesis/secretion of caltrin, calcium transport inhibitor protein of mammalian seminal vesicle

Effects of androgen status on the synthesis and secretion of rat caltrin have been studied by three different procedures: a) immunocytochemistry in seminal vesicle tissues; b) polyacrylamide gel electrophoresis and Western immunostaining of seminal vesicle secretion; and c) evaluation of trypsin inhibitory activity of the seminal vesicle secretion. Rat caltrin has been immunolocalized in cells of the secretory epithelium, specifically in the electron-lucent halo of secretory granules which store and transport proteins to the lumen. No caltrin immunoreaction was detected 14 days postcastration, and the ultrastructure of the epithelial cells was markedly altered. SDS-PAGE and Western blotting of the seminal vesicle secretion revealed alterations in the protein pattern and loss of the caltrin-related immunoreactive bands. The 54-kDa caltrin-precursor protein and the 6.2-kDa active caltrin were absent. Trypsin inhibitory activity of the seminal secretion was reduced about 50% in castrated animals. Daily testosterone administration restored both the protein pattern and immunoreactivity of the seminal vesicle secretion, and, as expected, reversed the morphological alterations of the gland after 7 days of treatment. Trypsin--inhibitor effect of the secretion also returned to normal levels after fourteen days of testosterone administration. Data suggest that the synthesis and secretion of caltrin are testosterone-dependent processes.

Electron microscopic immunolocalization of caltrin proteins in guinea pig seminal vesicles

Caltrins, the small, basic proteins of the seminal vesicle secretion that inhibit calcium transport into epididymal spermatozoa, and consequently the onset of the acrosome reaction and the hyperactivated motility, were localized in the epithelial cells and the lumen of the seminal vesicles of the guinea pig by an immunocytochemical procedure and electron microscopy. Rabbit antisera against each protein (caltrin I or II), and goat anti-rabbit IgG antiserum labeled with colloidal gold were used to detect the caltrin immunoreaction. The subcellular distribution of the gold labeling was occasionally localized in the rough endoplasmic reticulum but mainly within big secretory vacuoles containing low electron-dense material, which are components of the Golgi complex known as condensing vacuoles. These are involved in the intracellular transport, storage, and discharge of secretory proteins. Gold-labeled material released to the lumen was also detected. There was no clear evidence that the discharge was mediated by an exocytotic process. Immunoreaction was observed neither in the electron-dense core nor in the electron-lucent halo of the typical secretory granules of the epithelial cells of the seminal vesicles. Using light microscope immunocytochemistry, intense positive immunoreactivity was detected in the material secreted to the lumen but not on the epithelial cell layer. Only those cells undergoing a degenerative process and showing a picnotic nucleus and condensed cytoplasmic matrix exhibited detectable immunoreaction when gold label and silver intensification were applied. The same distribution of the immunoprobes was obtained by electron or light microscopy when antiserum to either I or II was used. It would appear that the two caltrin proteins of the guinea pig are synthesized in the rough endoplasmic reticulum of the epithelial cells and transported quickly to the Golgi complex where the secretory vacuoles (condensing vacuoles) are formed. The proteins are transported by the secretory vacuoles to the apical ends of the cells to be discharged into the lumen.

Structural reorganization of the rough endoplasmic reticulum without size expansion accounts for dexamethasone-induced secretory activity in AR42J cells

A striking reorganization of the rough endoplasmic reticulum (RER) from a tubulo-vesicular (TV-RER) to a stacked cisternal (SC-RER) configuration was observed when the secretory activity of AR42J cells, a cell line derived from a rat pancreatic acinar carcinoma, was induced by dexamethasone. Treatment with 10 nM dexamethasone resulted in a 6.6-fold increase in the intracellular and a 4.6-fold increase in the secreted amylase activity, respectively. On the basis of the morphometric analysis of thin-section electron micrographs it has been previously reported that this increase in secretory activity is accompanied by a 2.4-fold or 30-fold increase in the size of the RER. We have developed a new biochemical method to determine the size of the RER by quantifying the membrane-bound ribosomes. Using this procedure we did not detect any change in the size of the RER after induction of an active secretory state in AR42J cells. Electron microscopic observation showed the predominance of SC-RER in dexamethasone-treated cells compared to the abundance of TV-RER in control cells. Laser scanning confocal microscopy showed a patchy distribution of ER staining in dexamethasone-treated cells compared to more basal localization in control cells. On the basis of our observations we conclude that in AR42J cells the increase in secretory activity induced by dexamethasone is accompanied by a reorganization of the RER rather than by an increase in ER surface area, as reported by others. Our results suggest that SC-RER is a biosynthetically more efficient form of the RER, which is found predominantly in actively secreting cells.

Regulation of the epididymal glutathione peroxidase-like protein in the mouse: dependence upon androgens and testicular factors

The protein MEP24 was previously described as a glutathione peroxidase-like molecule specifically secreted by the mouse caput epididymidis. Recently, its binding to the head of spermatozoa was demonstrated. Here, the regulation of MEP24 expression was studied by analyzing transcriptional and translational activities in the epididymis (1) of adult mice castrated on day 60 and given various substitutive testosterone (T) treatments from day 90 and (2) of hemicastrated adult animals. In castrated mice, T treatment induced a significant rise in plasma T and 5 alpha-dihydrotestosterone (DHT) concentrations that greatly exceeded the control values. Owing to efficient regulation, however, the epididymal T and DHT levels were never higher than those of the controls. The restoration of MEP24 mRNA accumulation was complete when the epididymal DHT content returned to its normal value. However, when estimated in a cell-free system, the in vitro translatable MEP24 mRNA level never exceeded 70% of control values, even though the DHT and accumulated mRNAs were restored by 100% or more. In hemicastrates, the T content was normal on the castrated side, while the DHT content exhibited a significant decrease (47%). In this case, the MEP24 mRNA accumulation reached 88% of the normal value, but the translation rate, both in vitro and in vivo, was only about 50%. Ultrastructural studies showed that the normal rough endoplasmic reticulum organization in segment I cells is dependent upon the presence of testicular fluid in the epididymal duct lumen. Thus, this report shows that the MEP24 mRNA steady-state level is completely recovered in the presence of a normal epididymal DHT content, while restoration of the regulation of translation is just partial. This could be related to the cell organization but seems mainly dependent upon the presence of specific mRNA-associated factors which are probably under the control of androgens and/or molecules carried by the testicular fluid.

Synthesis and post-translational modifications of an epididymal androgen dependent protein family

During the annual cycle of the lizard Lacerta vivipara dramatic changes in the secretory activity of the epididymis were observed. These changes and changes in morphology correlate with the plasma and epididymal testosterone concentrations. The secretory proteins contain a major group of immunorelated components referred to as LI to L1X. They consist of a group of nine proteins Mr 19,000 which can be separated according to pI 3.5 to 8.7. Post-translational modifications may be responsible for their pI diversity. All the L proteins are glycosylated (fucose, N-acetylgalactosamine and or N-acetylglucosamine) but only LVI glycosylation was inhibited with tunicamycin. Phosphorylation is unique to LV protein and none of the L proteins are sulfated. All L proteins appeared sequentially during the annual cycle and in organotypic culture when incubated in the presence of testosterone (150, 500, 1000 nM) in a time dependent manner.

Effects of androgens on the transcription of secretory protein genes in rat seminal vesicle

Run-on transcription in isolated nuclei has been used to study the effects of testosterone on gene expression in rat seminal vesicles. General transcriptional rates were increased by about 6-fold with an additional 2- to 3-fold differential stimulation of the genes for secretory proteins IV and V. These transcriptional changes are insufficient to explain overall changes in cellular mRNA levels, indicating that androgens must also have major effects on post-transcriptional processing of RNA transcripts or on mRNA stability. Analysis of nuclear RNA by Northern blotting with intron probes suggests substantial androgen effects on primary transcript processing.

Analysis of oestrogen receptor dimerisation using chimeric proteins

Sequences essential for dimerisation have been identified in the hormone binding domain of the mouse oestrogen receptor by insertional and point mutagenesis and sequence comparisons reveal that equivalent residues may be conserved in other members of the nuclear hormone receptor superfamily. To assess functional compatibility of this region between members of the receptor superfamily, peptide sequences corresponding to the equivalent regions of the human androgen receptor and retinoic acid receptor have been substituted for the dimerisation domain of the mouse oestrogen receptor. The resulting chimeric proteins were analysed for high affinity DNA binding using a gel retardation assay and shown to bind with reduced affinity compared to the wild type oestrogen receptor. The reduction in DNA binding observed may result from the intramolecular incompatibility of functional elements within the hormone binding domain of nuclear hormone receptors.

Membrane biogenesis during B cell differentiation: most endoplasmic reticulum proteins are expressed coordinately

The induction of high-rate protein secretion entails increased biogenesis of secretory apparatus organelles. We examined the biogenesis of the secretory apparatus in the B cell line CH12 because it can be induced in vitro to secrete immunoglobulin (Ig). Upon stimulation with lipopolysaccharide (LPS), CH12 cells increased secretion of IgM 12-fold. This induced secretion was accompanied by preferential expansion of the ER and the Golgi complex. Three parameters of the rough ER changed: its area and volume increased 3.3- and 3.7-fold, respectively, and the density of membrane-bound ribosomes increased 3.5-fold. Similarly, the area of the Golgi stack increased 3.3-fold, and its volume increased 4.1-fold. These changes provide sufficient biosynthetic capacity to account for the increased secretory activity of CH12. Despite the large increase in IgM synthesis, and because of the expansion of the ER, the concentration of IgM within the ER changed less than twofold during the differentiation process. During the amplification of the rough ER, the expression of resident proteins changed according to one of two patterns. The majority (75%) of rough microsomal (RM) proteins increased in proportion to the increase in rough ER size. Included in this group were both lumenal proteins such as Ig binding protein (BiP), and membrane proteins such as ribophorins I and II. In addition, the expression of a minority (approximately 9%) of RM polypeptides increased preferentially, such that their abundance within the RM of secreting CH12 cells was increased. Thus, the expansion of ER during CH12 differentiation involves preferential increases in the abundance of a few resident proteins, superimposed upon proportional increases in most ER proteins.

Identification of two transactivation domains in the mouse oestrogen receptor

We have identified two discrete transactivation domains within the mouse oestrogen receptor whose relative activities vary according to the target promoter. One domain lies within the N-terminal region and is active in the absence of oestradiol. The second domain is contained within the C-terminal portion of the protein and depends upon oestrogen binding for its activity. The location and oestrogen dependence of this domain has been confirmed using chimaeric receptors containing the Lex A DNA binding domain. Although transactivation by the C-terminal domain is dependent upon ligand binding the analysis of receptor deletion mutants has demonstrated that these two functions are not entirely coincident.

Developmental pattern of androgen-regulated proteins in seminal vesicles from the mouse

Proteins from secretions or homogenates of mice seminal vesicles were analysed by polyacrylamide gel electrophoresis. In homogenates about 15 bands were differentially induced with molecular weights (MW's) of 12, 13, 14, 15, 15.5, 71, 120 and 140 kD, or repressed molecular weights of 12.5, 14.3, 28, 30, 53, 73, 90-105 kD). The effects of castration were reversed by testosterone and dihydrotestosterone but not by oestradiol, progesterone or corticosterone. When the androgen-dependence of proteins was investigated using radioactive methionine the protein spectra showed that about 12 bands with molecular weights of 13, 13.7, 14, 15, 15.5, 16, 20.5, 24, 37, 38.5, 56, 68, 96 and 180 kD were differentially induced or repressed by androgens. Of the induced proteins, those with low molecular weight (12-15.5 kD) were accumulated in significant amounts between 20 days and 30 days, coincident with the pubertal increase of androgens in the seminal vesicles. Those induced proteins with high molecular weight (71, 120 and 140 kD) appeared between 40 days and 60 days. The androgen-repressed proteins were strongly evident in immature males, but disappeared after day 40.

Molecular cloning of two cDNAs for related secretory proteins in lizard epididymis: gene expression during androgen-induced cell growth and secretion

Lizard epididymis is an androgen-dependent tissue which produces notably ten related secretory proteins (L-proteins, Mr 19,000) during the reproductive period. These proteins were synthesized in vitro as preproteins (Mr 25,000, 24,000, 23,500). A cDNA library in the plasmid pBr322 was constructed and two cDNA clones were isolated by differential hybridization according to the differential expression of the mRNAs in stages 1 and 6 of the annual reproductive cycle. Translations of mRNAs hybrid-selected by two clones (LV123, LV132) yielded proteins which were immunoprecipitated by the L-antiserum. These preproteins were processed in vitro into six peptides; four were encoded by mRNAs selected with the LV123 clone, the others by the LV132 clone. Only three bands were detected using Northern blot analysis suggesting that the L-family could be derived from various mRNAs and from post-translational maturations. Southern analysis of genomic DNA suggests that the L-mRNAs were encoded by at least two distinct genes which could exist in numerous copies. The L-gene expression was studied under various physiological conditions and was found to be androgen-dependent. Furthermore, the results suggest the presence of a translational regulation in the newly differentiated epithelial cells.

Functional structure and ultrastructure of seminal vesicles

The function of the seminal vesicles in animals and man is under androgen control. The use of a new marker of the seminal vesicle function, termed corrected fructose, demonstrates an association between serum testosterone levels and seminal corrected fructose levels. The human seminal vesicles secrete a variety of products, and there is good evidence of a close relationship between functions of the seminal vesicles and sperm motility. Some of their products of secretion, such as potassium, bicarbonate, prostaglandins, and prolactin, directly stimulate the motility of the sperm through actions at the level of the mechanisms of production of the energy necessary for the motion. Several constituents are secreted by the seminal vesicles, some of which have no specific functions.

Identification of constitutive and steroid-dependent transactivation domains in the mouse oestrogen receptor

We have identified two transactivation domains in the mouse oestrogen receptor whose activities depend on the target promoter. The major domain is contained within the C-terminal portion of the protein and depends upon oestrogen binding for its activity. The location and oestrogen dependence of this domain has been confirmed using chimaeric receptors containing the Lex A DNA binding domain. Although transactivation by the C-terminal domain is dependent upon ligand binding the analysis of receptor deletion mutants has demonstrated that these two functions are not entirely coincident. The second transactivation domain lies within the N-terminal region and is active in the absence of oestradiol. The differences in oestrogen requirement for the activity of the two transactivation domains may account for the partial agonist activity of certain antihormones.

A specific insulin receptor and tyrosine kinase activity in the membranes of Neurospora crassa

Cells of the wall-less ("slime") strain of Neurospora crassa possess specific high affinity insulin binding sites on their cell surface. 125I-labeled bound insulin was not displaced from these cells by insulin-like growth factor II (IGF-II), and was only weakly displaced by IGF-I and proinsulin. Cross-linking of 125I-labeled insulin with N. crassa cells using disuccinimidyl suberate resulted in the labeling of a single band of ca. 67 kDa m.w. on a polyacrylamide gel. Two proteins of ca. 66 and 59 kDa m.w. were purified from detergent solubilized plasma membrane preparations by passage over an insulin-agarose affinity matrix. Antibodies against an autophosphorylation site on the human and Drosophila insulin receptors (anti P2) immunoprecipitated a single phosphoprotein of ca. 50 kDa m.w. from detergent solubilized plasma membranes, which possessed protein tyrosine kinase activity when histone H2 was used as substrate.

Effects of differentiation state and post-castration time lapse on the epididymal response of the lizard to testosterone in vitro: changes in specific protein and mRNA levels

The epididymis of the viviparous lizard secretes large amounts of proteins among which L-proteins are prominent components. It undergoes great morphological and physiological modifications during its testosterone-controlled annual cycle. The effects of testosterone on L-proteins synthesis and L-mRNA concentrations were studied in cultures of organs regressed after castration. Of three tested serum supplements (2% Ultroser, 10% fetal calf serum, 10% calf serum) calf serum was shown to be essential for androgen-specific control of L-proteins synthesis. The duration of castration governed the in-vitro response to testosterone principally at the level of L-proteins synthesis. The onset of synthesis was delayed in 2-month post-castration explants, compared with 1-month post-castration explants, and was dissociated from appearance of the mRNA. This suggests that there is translational control of secretory proteins in the regressed epididymis. Conversely, the response to testosterone at the mRNA level was delayed in explants from animals castrated during a non-secretory state, compared with explants from animals castrated at the onset of secretion. These results, together with other data, suggest that expression of the L-proteins is under multifactorial control and that the influence of multiple controlling elements varies with the stage of differentiation.

Comparison of seminal vesicle secretory proteins of rodents using antibody and nucleotide probes

The copulatory vaginal plug is a conspicuous feature of rodent reproduction. The five major seminal vesicle secretory proteins of Rattus norvegicus (proteins I-V), which form the copulatory plug, constitute a closely related androgen-regulated family that appears to share a common evolutionary origin. The relationships between these rat proteins and the major seminal vesicle proteins of other rodents were explored using antibodies specific for the individual rat proteins. Immunoblotting of proteins separated by SDS-PAGE showed that the vesicular proteins of R. rattus are identical to those of R. norvegicus except for an additional protein related to protein III. No differences were seen in inbred and outbred strains of R. norvegicus. Of the major proteins of Mus musculus, one showed strong homology with rat protein II and three others were weakly homologous to proteins I, IV (or S) and V (or F); none showed homology to rat protein III. The only homology between the vesicular proteins of Mesocricetus auratus (Syrian hamster) and Meriones ungulatus (Mongolian gerbil) was with rat protein II while those of Cavia porcellus (guinea pig) showed no homology at all with the rat proteins. In addition, cDNA probes for rat genes IV and V both detected weak homologues in seminal vesicle RNA from mice but not guinea pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular cloning of the cDNA for androgen-dependent sperm-coating glycoproteins secreted by the rat epididymis

cDNA clones coding for two closely related androgen-dependent sperm-coating glycoproteins secreted by the rat epididymis were selected by screening an epididymal cDNA library constructed in lambda gt 11 with affinity-purified antibody directed against the glycoproteins. The largest clone of 956 nucleotides provided coding information for a protein of 246 amino acids of which the first 19 residues comprise a putative signal peptide sequence which when cleaved would produce a mature protein of 227 residues and a molecular mass of 26 kDa. Confirmation of the identity of the clone was provided by a match between the amino acid sequence predicted from the cDNA sequence and the actual amino acid sequence determined for a tryptic peptide fragment of one of the pure glycoproteins. It is probable that the primary amino acid sequence of the two glycoproteins is identical. Northern blot and slot-blot analysis revealed that the mRNA for the glycoproteins is approximately 1250 nucleotides long and that the concentration of the mRNA in the epididymis is androgen-dependent. The glycoproteins and their mRNAs were unique to the epididymis as determined by Western and Northern blots, respectively, since signals were absent from skin, brain, liver, kidney, heart, skeletal muscle and testis. Cross-reacting proteins of slightly smaller apparent molecular mass were detected in extracts of mouse and guinea-pig epididymis, but not rabbit or bull epididymis. Comparison with existing protein data bases revealed that the epididymal glycoproteins display significant sequence homology with yeast carboxypeptidase Y.

Tissue distribution, developmental profile and hormonal regulation of androgen-responsive secretory proteins of rat seminal vesicles studied by immunocytochemistry

The seminal vesicles of the rat synthesise large amounts of androgen-regulated secretory proteins. Indirect immunofluorescence cytochemistry and immunoblotting with monospecific polyclonal antibodies against three of the major secretory proteins (II, S and F) have been used to investigate the tissue distribution, subcellular localisation, androgen-regulation and developmental profile of secretory protein synthesis. There was no evidence for regional specialisation of the seminal vesicle epithelium; every epithelial cell synthesizes all three proteins via a classical secretory involving storage in secretory vesicles. Proteins S and II are contained within the same secretory vesicles. The time course of deinduction of proteins S and F after castration and their reinduction by testosterone closely followed that for their specific mRNAs described previously. During development, proteins S and F first appear between 10 and 15 days after birth. A protein immunologically related to seminal vesicle protein II is present in the lateral and dorsal lobes of the prostatic complex.

Androgen-regulated proteins of rat seminal vesicle secretion constitute a structurally related family present in the copulatory plug

All the major androgen-regulated secretory proteins of rat seminal vesicles have been purified in high yield from polyacrylamide gels using electroelution. In the process a sixth previously undocumented protein has been identified. Amino acid compositions of all the proteins are very similar and highly unusual, being high in lysine and arginine, and with 40-50% of the residues accounted for by serine, glycine and glutamate/glutamine. N-Terminal amino acid sequences for 3 of the proteins show that they are clearly the products of related genes. At least one of the other proteins is N-terminally blocked in vivo. Antibodies specific for each protein have been raised and provide evidence of structural similarity between the proteins. The antibodies were also used in immunofluorescence histochemistry with the rat copulatory plug, showing for the first time that all the major proteins of seminal vesicle secretion are components of this reproductive structure.

Influence of castration and androgen treatment on the synthesis of prostatic binding protein and the concentration of its mRNA in the rat ventral prostate

The regulation by androgens of the synthesis of prostatic binding protein (PBP), an abundant secretory protein of the rat ventral prostate, was studied by measuring the rate of incorporation of [3H]leucine into total protein and into PBP by prostatic tissue in vitro. PBP-specific synthesis dropped to 30% of the intact level after 3 days and to 5.5% after 7 days. Administration of androgens to 7 day-castrated rats reversed these changes: 36% of the control value was reached after 3 days of treatment and 70% after 5 days. The mRNAs of PBP were measured under similar conditions by means of dot hybridization, using C1-, C2- and C3-specific cDNA-clones. The 3 mRNAs followed a parallel course. They decreased to about 18% on the third day after castration and to about 2% after 7 days. Androgen treatment of 7-day castrated rats produced a small increase of these levels after 1 day. After 3 days 15% of the intact level was reached. The general similarity of the time course of PBP synthesis and PBP mRNA levels in castrated and androgen treated rats supports a transcriptional regulation mechanism, although there also is some evidence for an influence on protein synthesis in general.

Sequence organisation of rat seminal vesicle F gene: location of transcriptional start point and sequence comparison with six other androgen-regulated genes

Seminal vesicle F gene, encoding an androgen-regulated serine-rich structural protein of the rat copulatory plug, has been sequenced together with 5' and 3' flanking regions. The intron/exon arrangement of the gene deduced from restriction maps was confirmed. The major and possible minor transcriptional start points were located by primer extension analysis and S1 nuclease mapping. A published nucleotide sequence for seminal vesicle S gene which also encodes an androgen-regulated protein of the copulatory plug has been extended to allow comparison of F and S genes. The considerable sequence homology between the two genes confirms their evolutionary relatedness. Homology is especially high in their promoter regions and their transcriptional start points are identical. They share several regions of dyad symmetry including one just upstream of the promoter. The upstream regions of F and S genes were compared with those of five other androgen-responsive rodent genes in an attempt to identify common sequence motifs that might be involved in hormonal regulation of gene expression.