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)

The effects on the fertility of adult male rats of six new synthetic steroids: I, 3-cyano-5alpha-androst-1-en-17-one; II, the 17beta-acetate form of I; III, 17beta-hydroxy-5beta-cyano-androstan-3-one; IV, 6-methylpregnenolone; V, 17beta-hydroxy-17alpha-ethynyl-5beta-cyano-19-norandrostan-3-one; and VI, 19-norspiroxenone (oestr-4-en-3-one-spiro-17alpha-2'-[tetrahydrofuran]) have been tested. After 6 weeks of treatment with daily doses of 5 mg (I, II, III), 15 mg (IV) or 10 mg (V, VI) only steroid VI blocked the completion of spermatogenesis and reduced the number of foetuses sired in at least five females/male. Steroid VI also diminished seminal vesicular, prostatic, testicular and epididymal weights. It inhibited the testicular enzymes, 3beta-hydroxysteroid dehydrogenase-delta4-5-3-oxosteroid isomerase system, 17alpha-hydroxylase, and C17-20 lyase markedly, but did not affect the adrenal dehydrogenase-isomerase system. It depressed, strikingly, testicular and serum levels of testosterone and 5alpha-dihydrotestosterone and reduced pituitary and serum levels of FSH and LH. Although marked depression of target organ weights also occurred with steroids II, IV and V, and reduction of androgen levels and LH in the circulation with III, IV and V, only VI was a potent blocker of male fertility with the exception of a slight block of the siring of viable foetuses by steroids IV and V. The major difference in site of action of steroid VI from the others was the depression of pituitary and serum levels of FSH along with a marked diminution of testicular content of both testosterone and 5alpha-dihydrotestosterone. 19-Norspiroxenone in the rat is a potent anti-oestrogen without inherent oestrogenicity and is anti-uterotrophic. Thus, VI may affect male fertility by virtue of its potent anti-oestrogenic action in the hypothalamus or testis.
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PMID:Effects of new multi-site hormone blockers on the fertility of male rats. 127 Sep 48

We have investigated the effects of two 4-ene-steroid 5 alpha-reductase inhibitors, diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxamide (4-MA) and (4R)-5,10-seco-19-norpregna-4, 5-diene-3,10,20-trione (SECO), on testicular and epididymal androgen biosynthesis. Kinetic analyses revealed that both compounds inhibited epididymal DHT biosynthesis. 4-MA was a competitive inhibitor of epididymal nuclear and microsomal 4-ene-steroid 5 alpha-reductases (3-oxo-5 alpha-steroid: NADP 4-ene-oxidoreductase EC 1.3.1.22) with Kiapp values of 12.8 and 15.1 nmol/l compared to the respective Kmapp values of 185 and 240 nmol/l. Values for the Vmaxapp were always within 70-130% of the control. SECO at 1.0 mumol/l, also inhibited epididymal nuclear and microsomal 4-ene-steroid-5 alpha-reductases, causing respectively 2.9 and 5.2-fold increases in Kmapp. The Vmaxapp values were unchanged. However, SECO concentrations of 5 and 25 mumol/l abolished 4-ene-steroid 5 alpha-reductase activity at all testosterone concentrations. To examine the specificity of these compounds, we investigated their effects on the enzymes that convert pregnenolone to testosterone. Rat testis microsomes converted pregnenolone to testosterone via the 4-ene-3-oxo pathway, with the major metabolites being progesterone, 17-hydroxyprogesterone, 4-androstenedione and testosterone; some 17-hydroxypregnenolone was also formed. Very small amounts of dehydroepiandrosterone (DHA) and 5-androstenediol were detected. SECO, at a concentration that completely inhibited epididymal 4-ene-steroid 5 alpha-reductase activity, did not alter the metabolic profile of pregnenolone metabolism. However, 4-MA prevented the appearance of 4-ene steroids, and large quantities of 17-hydroxypregnenolone and DHA accumulated, suggesting that inhibition of the 3 beta-hydroxysteroid: NAD(P)+ oxidoreductase (EC 1.1.1.51) and 3-oxosteroid 5-ene-4-ene-isomerase (EC 5.3.3.1) [3 beta-hydroxysteroid dehydrogenase-isomerase] was occurring. Optimal conditions for the microsomal conversion of DHA to 4-androstenedione were determined; kinetic analyses of the 3 beta-hydroxysteroid dehydrogenase-isomerase activity revealed that 4-MA inhibited this reaction non-competitively, reducing Vmaxapp values to 25% of the control. The Kiapp determined from the intercept replot, was 121 nmol/l, and the Kmapp was always between 90 and 130% of the control value. It is concluded that SECO is more specific than 4-MA in its effects on androgen biosynthesis in the testis and epididymis and that both these drugs should provide useful tools in assessments of the relative contributions of 5 alpha-reduced androgens to androgen dependent processes.
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PMID:The effects of diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxamide (4-MA) and (4R)-5,10-SECO-19-norpregna-4,5-diene-3,10,20-trione (SECO) on androgen biosynthesis in the rat testis and epididymis. 370 62