STUDIES ON CONVERSION OF LABELED PREGNENOLONE TO PROGESTERONE BY OLIVE BABOON PLACENTAL CYTOTROPHOBLAST CELLS IN-VITRO

The experiments were designed to study the influence of a variety of s ubstances, which have been reported to affect placental steroid metabo lism, on pregnenolone metabolism by olive baboon placenta cells. Place ntae were obtained from six baboons by caesarian section between 100 a nd 110 days of pregnancy. The cells were isolated by enzyme digestion and Ficoll gradient separation and incubated in Ham's F10 media with 5 mu Ci [4,7, - 3H] pregnenolone in the presence or absence of indometha cin (0.1 mmol/l), dibutyryl cAMP (10 mmol/l), phorbol myristic acetate (10 nmol/l), 3-isobutyl-1-methylxanthine (0.5 mmol/l), calcium ionoph ore A23187 (1 mumol/l), and nordihydroguaiaretic acid (40 mug/ml). Con trol experiments were done using leucocytes, inactivated placental cel ls and Ham's F10 media. Time course and dose response studies were als o done. Placental cells converted pregnenolone to progesterone in a do se related manner. Addition of test compounds did not affect conversio n rates. It is concluded that further studies are needed for elucidati on of mechanisms that regulate progesterone synthesis in baboon placen tae.