Inhibition of steroidogenesis by luteal cells of early pregnancy in the rat in response to in vitro administration of a gonadotropin-releasing hormone agonist.

摘要: Abstract Previous studies from this laboratory have demonstrated that the administration of a gonadotropin- releasing hormone agonist (GnRH-Ag) in vivo early or mid-pregnancy to rats induces antifertility effects by suppressing luteal production progesterone (P 4 ) within 24 h with concomitant increse lipid droplets and decreses cytochrome P 450 side chain cleavage ( 450scc) enzyme its mRNA content. These observations suggest direct inhibitory effect GnRH-Ag on corpus luteum. Here we demonstrate suppressive vitro basal , pregnenolone 5 20α-dihydroprogesterone (20α-DHP) cells obtained during pregnancy rats. We further studied two key enzymes, namely 450scc 3β-hydroxysteroid dehydrogenase (3β-HSD), which participate conversion cholesterol amd respectively. observed doses GnRH-Ag, 10 −4 −7 M, suppress after 12 incubation cells; remained suppessed 48 incubation. Basal was also suppressed were incubated for M but failed alter these cells. 20α-DHP incubating both h. inhibited activity 3β-HSD protein content at all time periods measured. results GnRH exerts steroidogenesis. This inhibition is due and/or not an increase metabolites.