Influence of adrenal cortex on testicular activity in the toad during the breeding season

The aim of the present study was to determine the role of adrenals in gonad al activity in the mate toad during the breeding season. Exogenous administ ration of corticosterone or metapyrone for 6 days inhibited adrenal Delta(5 )-3 beta(delta 5-3 beta) hydroxysteroid (Delta(5)-3 beta- HSD) and testicul ar 17 beta (17 beta) hydroxysteroid dehydrogenase (17 beta-HSD) activities, decreased the serum levels of testosterone and inhibited spermatogenesis. When toads were treated with corticosterone a significant rise of serum cor ticosterone was noted while metapyrone treatment appeared to decrease serum corticosterone levers. It is concluded that adrenocortical hormone plays a n indirect role in testicular activity in toads during the breeding season.