Corticosteroid biosynthesis in vitro by testes of the grouper (Epinepheluscoioides) after 17 alpha-methyltestosterone-induced sex inversion

This study reports the unique compartmentalization of cortisol and 11-deoxy cortisol biosynthesis in vitro from [H-3]17 alpha -hydroxyprogesterone (17P ) in testicular tissues of groupers after sex inversion induced by 17 alpha -methyltestosterone (MT). Before MT implantation, the ovarian tissues prod uced only nonpolar metabolites. Following sex inversion some 6 months later , synthesis of these nonpolar metabolites was not detectable. Instead, cort isol and 11-deoxycortisol, with yields of about 3% and 14%, respectively, w ere synthesized together with two other polar metabolites. The corticostero ids and polar metabolites were distinctly nondetectable in ovarian tissues of the control fish throughout the experiment. While the significance of th is testicular synthesis of corticosteroids is presently unclear, it could b e related to the increased energy demands arising from the reorganization o f gonadal tissues during sex inversion. (C) 2000 Wiley-Liss, Inc.