Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In adult male rats treated with streptozotocin 6 weeks before the experiments, androgen-binding protein concentration was increased in testicular tissue by 33% (p less than 0.01) and reduced in epididymal tissue by 25% (p less than 0.005) in animals exhibiting severe hyperglycaemia as compared with animals remaining in normoglycaemia or moderate hyperglycaemia. Androgen-binding protein content was diminished in epididymal tissue by 40% (p less than 0.0005) but not changed in testicular tissue. If related to constant body weight, the sum of testicular and epididymal androgen-binding protein was identical in both normo- and hyperglycaemic animals. This disturbance in androgen-binding protein distribution may be the consequence of altered testicular secretion or impaired transport of androgen-binding protein from testes to epididymides.
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PMID:Effect of streptozotocin-induced hyperglycaemia on androgen-binding protein in rat testis and epididymis. 653 17

Adult anesthetized male rats were submitted to in vivo micropuncture of the seminiferous and epididymal tubules and reproductive tract vasculature to obtain fluids for analysis of testosterone, 5 alpha-dihydrotestosterone, and androgen-binding protein (ABP). Androgen and ABP concentrations were determined by RIA. The highest concentrations of testosterone (73.14 +/- 5.12 ng/ml) were in testicular interstitial fluid. A significant downhill concentration gradient exists between testosterone concentrations in testicular interstitial fluid and seminiferous tubule fluid (50.24 +/- 2.26 ng/ml); another significant decrease occurs between seminiferous tubule fluid and rete testis fluid (17.85 +/- 2.11 ng/ml). 5 alpha-Dihydrotestosterone concentrations were highest in intraluminal caput epididymidal fluids (58.73 +/- 6.48 ng/ml) as were ABP concentrations (33.30 +/- 2.40 mu leq/microliter). Intraluminal sperm concentrations were also determined, and from these data, fluid reabsorption by the efferent ducts and epididymal tubules were calculated. Eighty-nine percent of the fluid leaving the testis is reabsorbed between the rete testis and caput epididymidis, and 96% is reabsorbed between rete and cauda. It was calculated that large losses of androgen and ABP also occur from the lumen of the excurrent duct system. These losses may be due to metabolism, diffusion from the lumen, or uptake by cells.
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PMID:On the androgen microenvironment of maturing spermatozoa. 654 71

Androgen-binding protein (ABP) is present in the guinea-pig testis, epididymis and epididymal fluid. Guinea-pig ABP sediments as an approx. 4.6S species on sucrose gradients containing 0.01 M KCl. Electrophoresis on non-denaturing polyacrylamide gels indicated that specific androgen binding was present in epididymal cytosol, but not in plasma. Time-course studies indicated that binding equilibrium is approached in about 2.5 h; the dissociation half-time of [3H]5 alpha-DHT from guinea-pig ABP is 5.64 +/- 0.62 h (n = 6) at 4 degrees C. The relative affinities of some steroids for guinea-pig ABP in relation to 5 alpha-DHT = 1 are: testosterone = 0.55 +/- 0.13 (n = 4), estradiol = 0.14 +/- 0.03 (n = 4), the anti-androgen cyproterone acetate = 0.0025 +/- 0.0002 (n = 3). Guinea-pig ABP exhibited an equilibrium dissociation constant of 6.34 +/- 0.52 nM (n = 3) at 4 degrees C and there were 3.43 +/- 0.78 (n = 3) pmoles of binding sites per mg of protein when homogenates of the whole epididymis were assayed. The concentration of ABP was lowest in the caput-corpus region of the epididymis, highest in the proximal cauda, and intermediate in the distal cauda. Essentially all of the ABP present in the distal cauda was intraluminal, as evidenced by the fact that flushing of the duct eliminated most of the [3H]5 alpha-DHT binding activity.
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PMID:The presence of androgen-binding protein in the guinea-pig testis, epididymis and epididymal fluid. 689 45

Androgen-dependent epididymal proteins were investigated in the hamster. The stimulation of labelled amino acid incorporation, as well as the colour intensity of bands stained with Coomassie Blue after electrophoresis of the epididymal cytosol from castrated animals with and without androgen replacement, were used as semi-quantitative criteria for evaluation. These techniques allowed the identification of 6 androgen-sensitive bands (EP) with the following relative electrophoretic mobilities with respect to albumin: EP1 = 0.8; EP2 = 1.11; EP3 = 1.21; EP4 = 1.31; EP5 = 1.52; EP6 = 1.63. The proteins EP1, EP3 and EP4 were also found in fluid from the cauda epididymidis. Extraction of spermatozoa from the distal corpus and cauda epididymidis with 0.25 and 0.5 M-NaCl yielded appreciable amounts of EP2 and EP3 but these bands were not detected in extracts of spermatozoa from proximal segments. The approximate molecular weights were 651 400 for EP1, 42 500 for EP2, 23 800 for EP3, 20 400 for EP4, 26 100 for EP5 and 41 000 for EP6. All bands stained as glycoproteins with periodic acid--Schiff reagent.
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PMID:Identification of androgen-dependent glycoproteins in the hamster epididymis and their association with spermatozoa. 705 86

Glutathione S-transferases, a family of enzymes that catalyze the conjugation of glutathione to a variety of substrates, are present in rat epididymis. In order to study the hormonal regulation of these enzymes in this tissue, adult rats were orchidectomized and implanted with empty or androgen-filled polydimethylsiloxane capsules. Orchidectomy alone significantly decreased caput-corpus epididymal glutathione S-transferase activity toward 2 substrates, 1-chloro-2,4-dinitrobenzene and trans-4-phenylbut-3-en-2-one, but had no effect on transferase activity toward the third substrate, 1,2-dichloro-4-nitrobenzene. In contrast to these results, orchidectomy did not alter glutathione S-transferase activity towards these substrates in the cauda epididymidis. Androgen replacement with testosterone prevented the orchidectomy-induced decrease in caput-corpus glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene and trans-4-phenylbut-3-en-2-one and had no effect on transferase activity toward 1,2-dichloro-4-nitrobenzene. The effects of 5 alpha-reduced metabolites of testosterone were also studied. Both dihydrotestosterone and 5 alpha-androstan-3 alpha, 17 beta-diol maintained caput-corpus glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene, although a lower dose of dihydrotestosterone was sufficient; these 1 androgens were unable to maintain activity toward trans-4-phenylbut-3-en-2-one and caused a suprastimulation of activity toward 1,2-dichloro-4-nitrobenzene above control values. The third 5 alpha-reduced androgen studied, 5 alpha-androstan-3 beta, 17 beta-diol had no effect on the transferase activity toward any of the 3 substrates. These results demonstrate that the epididymal glutathione S-transferases are under separate control and are differentially regulated by testosterone and its 5 alpha-reduced metabolites.
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PMID:Regulation of epididymal glutathione S-transferases: effects of orchidectomy and androgen replacement. 708 27

Androgen-binding protein (ABP) was purified from caput epididymis of the rat by sequential chromatography on DEAE-Sepharose, hydroxylapatite, dihydrotestosterone-17 beta-hemisuccinyl-1,6-diaminohexane-Sepharose, and Sephadex G-150. The final product migrated as a single band corresponding to a peak of protein-bound [3H]dihydrotestosterone on polyacrylamide gel electrophoresis. A molecular weight of 100,000 was estimated by sedimentation equilibrium. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, subunits of Mr = 47,000 and 41,000 were observed. Amino acid analysis indicated ABP to be rich in leucine while nonpolar aminoacids totaled only 51%. Its carbohydrate content is 25%. Antibodies to purified ABP were raised in a rabbit and evaluated by immunodiffusion, immunoelectrophoresis, binding inhibition, radioimmunoassay, and immunocytochemistry. Immunoperoxidase staining localized ABP in the basal and adluminal regions of seminiferous tubules of rat testis and in secretory granules of cultured Sertoli cells. In principal cells of caput epididymis, ABP is concentrated in the supranuclear region known to contain morphological specializations for absorption. These immunocytochemical results confirm that ABP synthesized and secreted by Sertoli cells in the testis is transported to the epididymal duct via testicular fluid and is taken up by epithelial cells of the proximal segments.
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PMID:Androgen-binding protein. Purification from rat epididymis, characterization, and immunocytochemical localization. 719 73

Androgen binding protein in human seminal plasma (SPABP) which has a high affinity-low capacity for dihydrotestosterone (DHT) was measured by saturation-charcoal adsorption technique. No correlation was found between SPABP binding capacity for DHT and sperm count or motility, but there was a significant correlation between SPABP binding capacity per ejaculate and semen volume. In order to determine the source of this binding protein seminal plasma from vasectomized men was analyzed, split ejaculates were studied from normal volunteers and SPABP was compared from epididymal ABP and from serum testosterone-estradiol binding (TeBG) by isoelectric analysis. There was no significant difference in SPABP binding capacity in semen from vasectomized (293.2 +/- 84.2pM) and non-vasectomized men with azoospermia (289.6 +/- 108.6pM). Analysis of split ejaculates showed the following: 1) the sperm density was significantly greater in the first fraction; 2) the concentration of fructose was greater in the second fraction; 3) SPABP binding capacity was the same in both fractions. The isoelectric analyses showed that SPABP was distinctly different from epididymal ABP and serum TeBG. In these data, this DHT-binding protein is not the same as testicular ABP. It appears to originate from both the prostate and seminal vesicles.
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PMID:[Studies on the source of androgen binding protein (ABP) in human seminal plasma (author's transl)]. 719 52

Spermatogenesis is a process in the testis that involves meiotic cell division and spermiogenesis. The mechanisms of regulation and its associated proteins are mostly unknown. This publication shows the two-dimensional (2-D) gel electrophoresis protein map obtained from rat testis using nonlinear 3.5-10 immobilized pH gradients for the first-dimensional separation. Eighteen proteins were successfully identified in the SWISS-PROT protein database using amino acid analysis of proteins recovered from polyvinylidene difluoride (PVDF) membranes and verified for one of them by comparison with Anderson's rat liver reference map. Fourteen new polypeptides were identified and four were previously known. Two of these new proteins were closely related to the spermatogenetic process. T-complex protein 1 is expressed in large amounts in germ cells. Androgen-dependent sperm-coating glycoprotein is secreted by epididymal cells. In order to detect changes in protein expression during meiosis and spermiogenesis, spermatocytes and round spermatid cell populations were purified by centrifugal elutriation and compared. In this way several proteins not found in the spermatocyte 2-D images could be high-lighted. The sperm-coating glycoprotein was thus shown to be present in large amounts in round spermatids.
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PMID:Spermatocytes and round spermatids of rat testis: protein patterns. 749 70

Nuclear binding of androgen was examined, using R 1881, a synthetic androgen. The amount of androgen-receptor complexes bound to isolated nuclei was determined in isolated adipocytes from the epididymal (Epi), retroperitoneal (Ret), inguinal (Ing) and mesenteric (Mes) adipose tissues from intact and castrated rats. The binding was specific and saturable with a Kd in the nanomolar range. Binding was examined after 2 days and after 1 and 2 weeks after castration, showing a higher binding in the Mes tissue in comparison with Ing at all time-points (P < 0.05). Mes adipocytes showed a trend (0.05 < P < 0.1) to up-regulate their binding capacity 2 days after castration, and a significant (P < 0.05) downregulation 2 weeks after castration. Two days after castration, R 1881 binding, expressed per mg triacylglycerol (TG), was generally higher in the Mes region (P < 0.05). This was not fully significant in comparison with Epi tissue in intact rats. When expressed per cell the differences were somewhat diminished, due to differences in cell sizes. Androgen binding showed a negative correlation with TG-uptake in vivo (r = 0.85, P < 0.01), suggesting that a higher density of androgen receptors leads to a more inhibited lipid uptake. In conclusion, a specific androgen receptor was demonstrated in adipose tissue in rat, showing regional differences and a negative correlation with the lipid accumulation of the tissue.
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PMID:Androgen hormone binding to adipose tissue in rats. 776 46

Androgen-binding protein (ABP) in rat epididymal cytosol and sex hormone-binding globulin (SHBG) in rabbit serum and SHBG purified from human serum were active-site-directed photoaffinity radiolabeled with 17 alpha-[(E)-2-[125I]iodoethenyl]androstan-4,6-dien-17 beta-ol-3-one ([125I]1). The interaction of this compound with binding components in epididymal cytosol was dependent on exposure of the mixture to ultraviolet light and on the duration of exposure. Photolysis in the presence of [125I]1 and 5 alpha-dihydrotestosterone (5 alpha-DHT) resulted in a 40% inhibition of binding of [125I]1 to cytosolic components. These result indicate that, while [125I]1 interacted with 5 alpha-DHT binding sites, it also formed adducts with other sites. To characterize the labeled species, the photolysis mixture was subjected to electrophoresis under denaturing and reducing conditions. Autoradiography of the gel revealed that ABP and SHBG were labeled with [125I]1, but in cytosol and serum, higher and lower molecular weight components were also labeled. Purified SHBG was labeled, but no labeled contaminating protein was detected. The presence of 5 alpha-DHT completely inhibited [125I]1 photolabeling of human and rabbit SHBG and of ABP. However, in cytosol, the presence of 5 alpha-DHT also eliminated photolabeling to a component that may be albumin, but 5 alpha-DHT did not affect [125I]1 photolabeling of other contaminating proteins in cytosol. Thus, while [125I]1 is an effective photoaffinity radiolabel for ABP and SHBG, the observation that it also photolabels other proteins limits its practical use to the radiolabeling of purified ABP and SHBG preparations.
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PMID:Active-site-directed photoaffinity radioiodination of androgen-binding proteins. 779 27


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