A COMPARISON OF PROGESTERONE METABOLISM IN THE PREGNANT SHEEP AND GOAT: SOURCES OF PRODUCTION AND AN ESTIMATION OF UPTAKE BY SOME TARGET ORGANS

Abstract

SUMMARY: Sites of production and uptake of progesterone were compared in acute experiments in two sheep and two goats 119–126 days pregnant. In the two goats progesterone was produced mainly by the ovaries (up to 10 mg./day, placenta 0 mg./day) whereas in the two sheep the placenta made the largest contribution (up to 14mg./day, ovaries about 2 mg./day). Adrenal production was less than 2% of the ovarian output except in one goat (20%). In four out of five foetuses studied, umbilical arterial concentrations of progesterone were higher than umbilical venous ones. Δ⁵-3β-Hydroxysteroid dehydrogenase was demonstrated histochemically in the foetal adrenals but not the ovaries.