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 vitro metabolism of 17-hydroxyprogesterone by testes of the roach has been examined. There was a shift from synthesis of the 11-oxygenated androgens, 11-ketotestosterone, and androstenetrione at low substrate concentration to 17,20 alpha-dihydroxy-4-pregnen-3-one (17,20 alpha P) at high substrate. Glucuronides and sulfates were of significant importance 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 increased substrate. The results confirm that substrate affects the steroidogenic profile and that 3 hr is optimal time for such studies. Incubations of sperm with 17-hydroxyprogesterone gave predominantly 11-ketotestosterone at low substrate concentrations and 17,20 alpha P at high substrate. The synthesis of 11-ketotestosterone is demonstrated for the first time in teleost sperm.