STEROL 14-DEMETHYLASE P450 ACTIVITY EXPRESSED IN RAT GONADS - CONTRIBUTION TO THE FORMATION OF MAMMALIAN MEIOSIS-ACTIVATING STEROL

Sterol 14-demethylase P450 (P45014DM)-dependent formation of 1,4-dimet hylcholesta-8,14,23-trienol, that has been reported for a mammalian me iosis-activating sterol, in rat ovaries was confirmed. Transient eleva tion of ovarian P45014DM activity, that might be related to the female sexual cycle of rat, was observed. The P45014DM activity of immature ovaries was induced by pregnant mare's serum gonadotropin. These bets suggest the contribution of ovarian P45014DM to the gonadotropin-depen dent formation of the meiosis-activating sterol, and provide a clue to understanding the mechanism how gonadotropins initiate the resumption of meiosis of mammalian oocytes. It was also found that rat testicula r P45014DM participated in the production of 4.4-dimethylcholesta-8,24 -dienol that was reported for another meiosis-activating sterol isolat ed from bull testes. (C) 1996 Academic Press, Inc.