BIOSYNTHESIS OF 17,20-ALPHA-DIHYDROXY-4-PREGNEN-3-ONE, 17,20-BETA-DIHYDROXY-4-PREGNEN-3-ONE, AND 11-KETOTESTOSTERONE BY TESTICULAR FRAGMENTS AND SPERM OF THE ROACH, RUTILUS-RUTILUS

The effect of incubation time and substrate concentration on the in vi tro metabolism of 17-hydroxyprogesterone by testes of the roach has be en examined. There was a shift from synthesis of the 11-oxygenated and rogens, 11-ketotestosterone, and androstenetrione at low substrate con centration to 17,20 alpha-dihydroxy-4-pregnen-3-one (17,20 alpha P) at high substrate. Glucuronides and sulfates were of significant importa nce only at low substrate and long incubation times. There was a shift from 17,20 beta-dihydroxy-4-pregnen-3-one to 17,20 alpha P with incre ased substrate. The results confirm that substrate affects the steroid ogenic profile and that 3 hr is optimal time for such studies. Incubat ions of sperm with 17-hydroxyprogesterone gave predominantly 11-ketote stosterone at low substrate concentrations and 17,20 alpha P at high s ubstrate. The synthesis of 11-ketotestosterone is demonstrated for the first time in teleost sperm. (C) 1995 Academic Press, Inc.