Role of 17 beta-estradiol and progesterone in the regulation of synthesis and secretion of chorionic gonadotropin by the first trimester human placenta.

The role of 17 beta-estradiol and progesterone in the regulation of synthesis of chorionic gonadotropin (CG) by first trimester human placenta has been studied using 1,4,6 androstatriene 3-17-dione to block the synthesis of 17 beta-estradiol or tamoxifen to block its action at receptor level and RU486 to block the action of progesterone at the receptor level. Results indicate that the synthesis of CG is negatively modulated by 17 beta-estradiol and positively modulated by progesterone as judged by the change in the levels of immunoreactive CG, alpha- and beta-CG mRNA and in vitro translation, as well as biosynthesis of alpha- and beta-CG and, finally, nuclear run off transcription.