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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat epididymal tubules maintained in organ culture for 3 days respond to the addition of androgens to the culture media (testosterone and dihydrotestosterone 1 x 10-minus 5 m and 1 x 10-minus 7 m) with an increased incorporation of amino acids into acid-insoluble material. Significant androgenic stimulation is observed only 24 h after addition of hormone, while an inhibitory effect is found at earlier periods. The stimulation seems to be specifically produced by androgens; it is blocked by cyproterone acetate and is not elicited by oestradiol-17beta or corticosterone. The process appears to involve RNA synthesis since actinomycin D suppresses the stimulatory effect of androgen. Evidence suggests that cAMP production is not a primordial step in the response to androgen since dibutyryl cAMP did not mimick the androgenic effect, theophylline did not potentiate the response and alpha,beta-methylene ATP, which competitively inhibits adenyl cyclase, failed to alter the androgenic effect. Radioactive testosterone and dihydrotestosterone added to the culture media showed a preferential intranuclear localization as well as extensive metabolism. DHT was found to be the principal intranuclear steroid.
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PMID:The influence of androgens on protein synthesis by cultured rat epididymal tubules. 16 37

A specific androgen binding protein has been demonstrated in the seminal plasma of adult Ram. This protein binds especially to 5 alpha-DHT and testosterone and much lower to oestradiol-17 beta. Its characteristics such as Ka (in order 10(9) M(-1) at 4 degrees C), relative mobility (Rf) and its specificity are similar to those of the androgen binding protein (ABP) of the Rete Testis Fluid and the epididymal plasma of the Ram. It is probable that this protein secreted from the testis, crosses the epididymis before being secreted in the seminal plasma at the moment of the ejaculation.
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PMID:[Demonstration of a specific androgen binding protein (ABP) in the seminal plasma of the ram]. 41 95

Infertile spermatozoa from the proximal corpus epididymidis will become fertile when this epididymal segment is cultured 24 h in vitro with 5alpha-dihydrotestosterone (5alpha-DHT). The effect of antiandrogens and inhibitors of RNA and protein synthesis upon this 5alpha-DHT-induced sperm maturation was investigated. The response to 5alpha-DHT was abolished by cyproterone acetate, SKF 7690, actinomycin D, cycloheximide, puromycin, and the aminonucleoside analog of puromycin. Addition of cyproterone acetate or actinomycin D to a suspension of distal corpus spermatozoa did not change their fertilizing ability. Culture of segments of the distal corpus for 24 h with the same antiandrogens and RNA and protein synthesis inhibitors did not change the fertilizing ability of spermatozoa. These results indicate that the development of the sperm-fertilizing ability observed in the proximal corpus epididymidis in vitro in response to 5alpha-DHT is dependent upon binding of 5alpha-DHT and synthesis of new RNA and protein molecules by the target cell. They also indicate that antiandrogen and inhibitors of RNA and protein synthesis do not have a nonspecific toxic effect on spermatozoa during the time period studied. It is likely that the target cells are the epididymal epithelial cells rather than the spermatozoa themselves.
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PMID:The maturation of rabbit epididymal spermatozoa in organ culture: inhibition by antiandrogens and inhibitors of ribonucleic acid and protein synthesis. 74 83

Cytosol prepared from epididymides of sexually immature (21-23-day-old) rats contains a macromolecular binding component for estradiol-17 beta. This binding moiety sediments as an 8-S species on 5-20% sucrose gradients containing 0.01 M KCl. Under conditions of high ionic strength (0.4 M KCl) the 8-S peak of estradiol binding is shifted to the 4-S region, suggesting dissociation of receptor aggregates. Time-course studies indicated that binding equilibrium was essentially achieved after 2 hours incubation at 0 degrees C. Although unlabeled estrone and estriol are capable of inhibiting [3H]estradiol binding to epididymal cytosol, they are less effective than unlabeled estradiol. Unlabeled 5 alpha-dihydrotestosterone (5 alpha-DHT) at a 100-fold molar excess did not cause a statistically significant inhibition of [3H]estradiol binding. Unlabeled estrogens, but not unlabeled 5 alpha-DHT or cortisol (at the concentrations used), were capable of displacint [3H]estradiol from its binding sites. The dissociation of [3H]estradiol from the binding component is very slow, with half-time of dissociation being greater than 16 hours. The epididymal estrogen binder is saturable at low concentrations of ligand. The dissociation constant was of the order of 10(-11)M and the concentration of binding sites was approximately 10(-14) mol/mg protein. This estrogen binder has the characteristics which are usually attributed to steroid receptors and is clearly different from the testicular androgen-binding protein and the epididymal androgen receptor.
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PMID:The presence of an estradiol binding component in cytosol from immature rat epididymides. 83 16

The ability to form androgen conjugates and the hormone dependency of the conjugating enzymes have been studied in the rat epididymis. Following the in vitro incubation of 3H-testosterone with epididymal slices from intact and castrated rats, the radioactivity recovered was partitioned between water and ether. Examination of the water soluble radioactivity demonstrated the presence of glucuronides and sulfates. The total radioactivity in the conjugate fraction was the same for both intact and castrated animals. However, castrated rats showed a 3-fold increase in the glucuronide fraction with a corresponding decrease in the formation of sulfates. Characterization of the ether soluble radioactivity after solvolysis of the conjugate fraction from castrated animals, showed DHT (17beta-hydroxy-5alpha-androstan-3-one) and 3alpha-diol (5alpha-andro-stane-3alpha, 17beta-diol) to be the main metabolites. After beta-glucuronidase hydrolysis of the same, only 3alpha-diol could be demonstrated at a significant level, although traces of DHT and delta16 compounds were present. Corresponding hydrolysis of the water phase from incubation of epididymis from intact rats, demonstrated a marked quantitative difference. Here approximately 40% of the conjugated aglycones consisted of delta16 compounds, whilst only about 12% was comprised of 3alpha-diol. The preferential conjugation of DHT and 3alpha-diol to a sulfate radical was demonstrated in both intact and castrated rats. Since the conjugated delta16 compounds were detected only in the epididymis from intact animals, it is possible that these are formed by the spermatozoa.
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PMID:Androgen metabolism by rat epididymis. 4. The formation of conjugates. 94 Nov 82

The pattern of androgenic metabolites in blood, muscle, caput and cauda epididymidis has been investigated in functionally hepatectomized 24 hours castrated rats, 3 hours after the intra-muscular injection of 200 muCi of 3H-3H-3alpha-diol. Identification of the radioactive metabolites showed only negligible differences between the epididymal regions. In both caput and cauda the main metabolite was DHT (17beta-hydroxy-5alpha-androstane-3-one); 3alpha- and 3beta-diol, androsterone (3alpha-hydroxy-5alpha-androstane-17-one), 5-A-dione (5alpha-androsterone-3, 17-dione), delta16-3alpha-01 (kalpha-androst-16-en-3alpha-01), delta16-3beta-01 (5alpha-androst-16-en-3alpha-01) and delta16-3-one (5alpha-androst-16-en-3-one) were also present. Androsterone and 3alpha-diol were the predominant metabolites in blood and muscle. No delta16 compounds could be detected and in constrast to epididymis, more than 50% of the radioactivity was associated with polar compounds. From determination of total radioactivity, it was seen that retention by epididymis varied from two to four times that of muscle. Purification and identification of the radioactivity associated with the nuclear fraction demonstrated that DHT was the only nuclear bound androgen. It is suggested from these results that at least one effect of 3alpha-diol on the rat epididymis is exerted through its conversion to DHT.
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PMID:Androgen metabolism by rat epididymis. 5. Metabolic conversion and nuclear binding after injection of 5alpha-androstane-3alpha, 17beta-diol, in vivo. 101 38

The in vivo and in vitro metabolism of 3H-testosterone by rat epididymis and the changes in epididymal weight have been studied after castration and treatment with anti-androgens. The utilization of 3H-testosterone was greatly reduced after castration as was the formation of 5alpha-reduced 17 beta-hydroxy metabolites. The formation of the 17 -keto metabolites was unaffected. Castration had no effect on the ratio between water and ether soluble radioactivity. Administration of testosterone propionate, necessary for giving normal stimulated prostate weight (150 mug/day), restored the metabolism of testosterone to approximately normal values. Estradiol benzoate and progesterone inhibited metabolism of testosterone in vitro and greatly reduced the formation of DHT (17 beta-hydroxy-5alpha-androstan-3-one) and 3 alpha-diol(5 alpha-androstane-3 alpha-17 beta-diol) by experiments both in vivo and in vitro. No effect of cyproterone acetate could be demonstrated on either the in vitro or in vivo metabolism of testosterone. Castration for 14 days reduced the epididymal weight to about 30% of that found in intact animals. Administration of testosterone propionate restored the epididymal weight to about 80% of normal. Estradiol benzoate and cyproterone acetate given to intact rats led to a decrease in the epididymal weight. Progesterone had no such effect. In 14 days castrated rats receiving testosterone propionate all three anti-androgens reduced the weight of the epididymis. In conclusion, our results show that the metabolic conversion of testosterone in epididymis to DHT and 3 alpha-diol is dramatically dependent on the hormonal status of the animal; castration or treatment with anti-androgens causes a reduced formation of the "active" androgens whilst testosterone replacement treatment restores the metabolism of testosterone to normal.
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PMID:Androgen metabolism by rat epididymis. 3. Effect of castration and anti-androgens. 126 92

The fertilizing ability of spermatozoa from epididymal tubules maintained in organ cultures from 1 to 7 days was assessed after artificial insemination into receptive does. It was found that spermatozoa from the distal corpus which were already capable of fertilizing eggs prior to the cultures retain this ability for 1 day without addition of hormone and for 3-4 days when testosterone (0.5 mug/ml) or 5alpha-dihydrotestosterone (0.5 mug/ml) is added to the culture medium. Spermatozoa from the proximal corpus which were not capable of fertilizing eggs prior to the cultures remain so after 1 day in cultures without addition of hormone. Testosterone, 5alpha-dihydrotesterone, 3alpha-androstanediol, or 3beta-androstanediol was added to cultures of proximal corpus at a concentration of 0.5 mug/ml. Only with 5alpha-DHT is the mean percentage of fertilization significantly higher than the percentage obtained without addition of hormone. Insulin does not potentiate the effect of 5alpha-DHT on sperm fertilizing ability. Epithelial growth factor is ineffective. Spermatozoa from the caput epididymidis kept in cultures for 1 to 4 days remain infertile. The results are discussed in light of the morphological findings presented in the preceding communication and in relation to the physiological requirement for sperm maturation in the epididymis.
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PMID:The effects of testosterone, 5alpha-dihydrotestosterone, 3alpha-androstanediol, and 3beta-androstanediol on the maturation of rabbit epididymal spermatozoa in organ culture. 126 23

Male mouse urogenital ridges (URs) at 15.5 days of gestation (vaginal plug = day 0) containing Wolffian (WDs) and Mullerian ducts were cultured for 4 days with or without gonads in serum-free medium (1:1 mixture of Dulbecco's modified Eagle's medium and Ham's F-12 supplemented with insulin, transferrin, cholera toxin, epidermal growth factor, and BSA). URs without gonads were grown in serum-free medium with testosterone (T, 10(-7) M), 5 alpha-dihydrotestosterone (DHT, 10(-8) M), T (10(-7) M) plus cyproterone acetate (antiandrogen, 10(-5) M), or T (10(-8) M) plus 390 MSD (17 beta-N, N-diisopropylcarbamoyl-4-aza-5 alpha- androstan-3-one, an inhibitor of 5 alpha-reductase, 10(-5) M). After 4 days of culture the number of epididymal curvatures that appeared in the upper portion of WDs were quantified. DNA content of URs grown in serum-free medium was also measured. Both T and DHT increased DNA contents in a dose- (T = 10(-8) to 10(-10) M, DHT = 10(-9) to 10(-11) M) and time-dependent manner. DHT was approximately 10-fold more effective than T in eliciting epididymal coiling and increasing DNA content of URs. The effects of T or DHT were mimicked by coculture with fetal testes. Epididymal coiling and an increase in DNA content occurred in URs grown in the presence of T plus 390 MSD. By contrast, URs cultured without androgens or with T plus cyproterone acetate failed to undergo epididymal coiling and to increase DNA content. The conversion rate per mg protein of [1 beta, 2 beta-3H]T into [3H]DHT was 0.30-fold lower in 15.5 day URs cultured over a 4-day period in comparison to urogenital sinuses whose development is known to be dependent upon DHT. These data suggest that T is an important hormone in the development of the upper portion of WDs, although it is not possible to exclude a role for DHT in the development of the epididymis.
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PMID:In vitro androgen-induced growth and morphogenesis of the Wolffian duct within urogenital ridge. 182 79

Previous results obtained with a model system of human epididymal tubules maintained in organ culture suggested that androgenic stimulation of this tissue resulted in responses similar to those obtained in epididymides of experimental animals under physiological conditions, as well as in other human androgen-dependent tissues. In this instance we have explored the possible influence of androgens on the activity of the androgen-converting enzymes 5 alpha-reductase and 17 beta-dehydrogenase. Activity of the former enzyme increases significantly during the culture period but no differences were found among the cultured groups, regardless of the addition of androgen. On the other hand, the activity of 17 beta-dehydrogenase was unchanged in all the experimental conditions tested. The co-culture of the tissue with explants of human testis was without effect. More than 85% of the activity of both enzymes was found localized in a fraction enriched in epithelial cells. Histological observation of the cultured tissues showed a marked disorganization of the pseudostratified epithelium in the absence of androgen while the inclusion of DHT in the media partially prevented these changes. We conclude that, under the conditions employed in these experiments, the activity of the enzymes studied is not influenced by androgens.
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PMID:The effect of in vitro androgen stimulation upon androgen metabolism and trophic parameters in cultured human epididymis. 254 Jun 81


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