THE METABOLISM OF SMALL AND OF LARGE AMOUNTS OF PROGESTERONE IN MAN

Abstract

ABSTRACT The metabolism of small and of large amounts of progesterone has been studied in two adrenalectomised ovariectomised women. After the injection of (4-14C) progesterone combined with 25 or 300 mg of unlabelled progesterone, the daily excretion of metabolites was serially studied. The amounts of radioactivity recovered in the free, glucuronide and sulphate fractions were determined and an increase in the sulphate fraction noted on the larger dose of hormone. In the glucuronide fraction which contained the majority of the extractable radioactivity, no alteration in the countercurrent distribution or chromatographic pattern of metabolites was noted with size of dose. Polar metabolites bearing one or more additional hydroxyl groups were quantitatively important but it was confirmed that 5β-pregnane-3α,20α-diol was the major identifiable metabolite. Some evidence was obtained that the complete reduction of steroid hydroxyl and ketone groups may occur to a small extent. Urinary progesterone, at least in part, was found to behave like an unstable enol-glucuronide. Levels of progesterone in urine during pregnancy and the luteal phase of the menstrual cycle were higher than during the follicular phase.