PRODUCTION RATE OF PROGESTERONE IN HUMAN MIDPREGNANCY

Abstract

ABSTRACT Progesterone-4-14C was injected i. v. into three women in midpregnancy, and the amount of steroid responsible for dilution was determined by the isotope dilution method from the specific activity of pregnanediol diacetate isolated from urine collected for 24 h. Progesterone-4-14C was injected i. v. into a woman in midpregnancy one week before and immediately after removal of the placenta (and foetus). The daily amount of steroid responsible for dilution was determined as above on 4 consecutive days before and after removal of the conceptus. From the data the following could be calculated: The rate of progesterone production in midpregnancy: 75.5 mg/24 h. About 70% of this is produced by the placenta and about 30% by extraplacental sources. The amount of steroid stored in tissues and participating in the dilution: 27.4 mg. The extra-placental production of progesterone decreases after removal of the placenta.