A comparative study of progesterone synthesis by term human fetal amnion and chorion.
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.
Gunasegaram
R
R
University Department of Obstetrics and Gynecology, National University Hospital, Singapore.
Peh
K L
KL
Loganath
A
A
Chow
W P
WP
Chew
P C
PC
Shanmugaratnam
S
S
D000650:Amnion / Q000378:metabolism*; D002823:Chorion / Q000378:metabolism*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*; D014316:Tritium
D014316:Tritium; D011374:Progesterone; D011284:Pregnenolone