[Effect of steroids on the formation of progesterone in the fetal membrane].

Recently, there have been some reports on the capacity of steroid metabolism of the fetal membrane. However, the mechanism of its regulation and its physiological meaning are not known. The authors therefore studied the progesterone (P4) producing capacity of the membrane and the effects of various types of sex steroids on it, using membrane cells. The membranes collected at the times of normal transvaginal deliveries (labor pains (+) group) and elective cesarean sections (labor pains (-) group) were separated into the decidua (D), chorion (C) and amnion (A), and were treated with collagenase to form free membrane cells. They were then incubated and studied for the conversion of pregnanolone (P5) which was added into P4 as a substrate. The effects of estradiol (E2), dehydroepiandrosterone (DHA) and testosterone (T) on the conversion were also studied. The following results were obtained: 1) In the labor pain (+) group, C, D and A demonstrated the capacity to convert P5. The conversions in C and D were linearly dose-responsive in the P5 dose ranges of 0-1,000 ng/ml and 100-1,000 ng/ml, respectively. By contrast, there was no linear dose-response relationship in the conversion in A. 2) The production of P4 in C was significantly inhibited by the addition of E2, DHA and T. 3) The production of P4 in A and D was not affected by other steroids. 4) In the labor pain (-) group, the production of P4 in C was not inhibited by E2 and DHA.(ABSTRACT TRUNCATED AT 250 WORDS)