Human chorionic gonadotropin-induced spermiation in Bufo arenarum is not mediated by steroid biosynthesis.
This study employed an in vitro system to identify potential steroidal mediators of spermiation in Bufo arenarum. Testicular fragments were incubated for 2 h at 28 degrees. Spermiation was induced by 10 IU human chorionic gonadotropin (hCG) and the effect of different inhibitors of steroid biosynthesis was analyzed. Cyanoketone (10(-5)-10(-6) M), an inhibitor of 3-oxo-4-ene steroid biosynthesis, did not block hCG-inducing activity even when biosynthesis of 3-oxo-4-ene steroids and its reduced metabolites was inhibited by 95%. Aminogluthetimide at a concentration that inhibited testosterone biosynthesis (10(-4) and 10(-5) M) did not alter hCG actions. Similar results were obtained with spironolactone, an inhibitor of 17alpha-hydroxylase/17-20 lyase activity. No spermiation-inducing activity was found with different steroids (progesterone, 17-hydroxypregnenolone, 17, 20alpha/beta-dihydroxy-4-pregnene-3-one, estradiol, testosterone, etc.). It is concluded that spermiation induced by hCG is not steroid mediated in B. arenarum.
PRHOM-CONICET and Laboratorio de Endocrinología Comparada, Universidad de Buenos Aires, Buenos Aires, C1428EHA, Argentina. apozzi@bg.fcen.uba.ar
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D015096:3-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors; D000616:Aminoglutethimide / Q000494:pharmacology; D000728:Androgens / Q000494:pharmacology; D000818:Animals; D002022:Bufo arenarum / Q000502:physiology*; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000037:antagonists & inhibitors; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003489:Cyanoketone / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D011374:Progesterone / Q000494:pharmacology; D013091:Spermatogenesis / Q000187:drug effects*; D013148:Spironolactone / Q000494:pharmacology; D013254:Steroid 17-alpha-Hydroxylase / Q000037:antagonists & inhibitors; D013256:Steroids / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000494:pharmacology; D013737:Testis / Q000187:drug effects / Q000378:metabolism; D013739:Testosterone / Q000096:biosynthesis
D000728:Androgens; D006063:Chorionic Gonadotropin; D004791:Enzyme Inhibitors; D013256:Steroids; D000616:Aminoglutethimide; D013148:Spironolactone; D013739:Testosterone; D003489:Cyanoketone; D011374:Progesterone; D015096:3-Hydroxysteroid Dehydrogenases; D013254:Steroid 17-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme