Studies On Conversion Of Labeled Pregnenolone To Progesterone By Baboon Placental Cytotrophoblast Cells In Vitro

Abstract

The experiments were designed to study the influence of a variety of substances, which have been reported to affect placental steroid metabolism, on pregnenolone metabolism by olive baboon placenta cells. Placentae were obtained from six baboons by caesarian section between 100 and 110 days of pregnancy. The cells were isolated by enzyme digestion and Ficoll gradient separation and incubated in Ham's F10 media with 5µ Ci [4,7, — 3H] pregnenolone in the presence or absence of indomethacin (0.1 mmol/1), dibutyryl cAMP (10 mmol/l), phorbol myristic acetate (10 nmol/l), 3-isobutyl-1-methylaxanthine (0.5 mmol/l), calcium ionophore A23187 (1 µmol/l), and nordihydroguaiaretic acid (40 µg/ml). Control experiments were done using leucocytes, inactivated placental cells and Ham's F10 media. Time course and dose response studies were also done. Placental cells converted pregnenolone to progesterone in a dose related manner. Addition of test compounds did not affect conversion rates. It is concluded that further studies are needed for elucidation of mechanisms that regulate progesterone synthesis in baboon placentae.