title: A comparative study of progesterone synthesis by term human fetal amnion and chorion.
abstract: Activity of 3 beta-hydroxysteroid dehydrogenase-5, 4-en isomerase was investigated with [7n-3H] pregnenolone as substrate in the homogenates of amnion and chorion collected from women (n = 6, age 20-34 years) after spontaneous labour at term (37-40 weeks gestation) from uncomplicated pregnancies. Controls were heat-denatured homogenates instead of fresh homogenates. Reverse-isotope dilution analysis gave positive identification of [3H] progesterone in all incubations of viable tissues. This metabolite was not evident in the controls. The extent of enzymic conversion of chorion, 1.4-31.1% was consistently higher than that of the amnion, 0.66-1.7%. The results show that the human fetal membranes can be a source of progesterone during pregnancy. The metabolic capability may have physiological significance in the induction and progression of labour to parturition.
authors.affiliation: University Department of Obstetrics and Gynecology, National University Hospital, Singapore.
authors.forename: R
authors.initials: R
authors.lastname: Gunasegaram
authors.forename: K L
authors.initials: KL
authors.lastname: Peh
authors.forename: A
authors.initials: A
authors.lastname: Loganath
authors.forename: W P
authors.initials: WP
authors.lastname: Chow
authors.forename: P C
authors.initials: PC
authors.lastname: Chew
authors.forename: S
authors.initials: S
authors.lastname: Shanmugaratnam
mesh_terms: D000650:Amnion / Q000378:metabolism*; D002823:Chorion / Q000378:metabolism*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*; D014316:Tritium
chemical_list: D014316:Tritium; D011374:Progesterone; D011284:Pregnenolone