Human Chorionic Gonadotropin-Induced spermiation in Bufo arenarum is not mediated by steroid biosynthesis

POZZI AG; CEBALLOS N

GENERAL AND COMPARATIVE ENDOCRINOLOGY

Elsevier

Lugar: Londres; Año: 2000 vol. 119 p. 164 - 171

0016-6480

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°. Spermiation was induced by 10 IU human chorionic gonadotropin (hCG) and the effect of different inhibitors of steroid biosynthesis was analyzed. Cyanoketone (1025–1026 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 (1024 and 1025 M) did not alter hCG actions. Similar results were obtained with spironolactone, an inhibitor of 17a-hydroxylase/17-20 lyase activity. No spermiation-inducing activity was found with different steroids (progesterone, 17-hydroxypregnenolone, 17,20a/b-dihydroxy-4-pregnene-3-one, estradiol, testosterone, etc.). It is concluded that spermiation induced by hCG is not steroid mediated in B. arenarum. in vitro system to identify potential steroidal mediators of spermiation in Bufo arenarum. Testicular fragments were incubated for 2 h at 28°. Spermiation was induced by 10 IU human chorionic gonadotropin (hCG) and the effect of different inhibitors of steroid biosynthesis was analyzed. Cyanoketone (1025–1026 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 (1024 and 1025 M) did not alter hCG actions. Similar results were obtained with spironolactone, an inhibitor of 17a-hydroxylase/17-20 lyase activity. No spermiation-inducing activity was found with different steroids (progesterone, 17-hydroxypregnenolone, 17,20a/b-dihydroxy-4-pregnene-3-one, estradiol, testosterone, etc.). It is concluded that spermiation induced by hCG is not steroid mediated in B. arenarum.