title: Role of oestradiol-17 beta in the regulation of synthesis and secretion of human chorionic gonadotrophin by first trimester human placenta.
abstract: Inhibition of aromatase, a key enzyme in the biosynthesis of oestradiol-17 beta, by the addition of 1,4,6-androstatrien-3,17-dione resulted in a significant increase in the levels of immunoreactive human chorionic gonadotrophin (hCG) in the medium and tissue. This increase was partially reversed by the simultaneous addition of oestradiol-17 beta. These effects on the levels of immunoreactive hCG were also reflected by the increased levels of mRNA specific for the alpha and beta subunits of hCG following the addition of the aromatase inhibitor. However, addition of tamoxifen resulted in a drastic decrease in the levels of both the messages. Based on these results, it is suggested that the synthesis of hCG is negatively modulated by oestradiol-17 beta in the human placenta.
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore.
authors.forename: S C
authors.initials: SC
authors.lastname: Sharma
authors.forename: P
authors.initials: P
authors.lastname: Purohit
authors.forename: A J
authors.initials: AJ
authors.lastname: Rao
mesh_terms: D000735:Androstenedione / Q000494:pharmacology*; D047072:Aromatase Inhibitors; D006063:Chorionic Gonadotropin / Q000096:biosynthesis* / Q000378:metabolism; D018997:Chorionic Gonadotropin, beta Subunit, Human; D004958:Estradiol / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D015292:Glycoprotein Hormones, alpha Subunit / Q000096:biosynthesis; D006801:Humans; D007700:Kinetics; D010446:Peptide Fragments / Q000096:biosynthesis; D010920:Placenta / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011374:Progesterone / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D013629:Tamoxifen / Q000494:pharmacology
chemical_list: D047072:Aromatase Inhibitors; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D015292:Glycoprotein Hormones, alpha Subunit; D010446:Peptide Fragments; D012333:RNA, Messenger; D013629:Tamoxifen; D000735:Androstenedione; D011374:Progesterone; D004958:Estradiol