R. Gunasegaram et al., A COMPARATIVE-STUDY OF PROGESTERONE SYNTHESIS BY TERM HUMAN FETAL AMNION AND CHORION, Journal of perinatal medicine, 23(5), 1995, pp. 371-377
Activity of 3 beta-hydroxysteroid dehydrogenase-5, 4-en isomerase was
investigated with [7n-H-3] pregnenolone as substrate in the homogenate
s of amnion and chorion collected from women (n = 6, age 20-34 years)
after spontaneous labour at term (37-40 weeks gestation) from uncompli
cated pregnancies. Controls were heat-denatured homogenates instead of
fresh homogenates. Reverse-isotope dilution analysis gave positive id
entification of [H-3] progesterone in all incubations of viable tissue
s. This metabolite was not evident in the controls. The extent of enzy
mic 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 membr
anes can be a source of progesterone during pregnancy. The metabolic c
apability may have physiological significance in the induction and pro
gression of labour to parturition.