Specific tissue metabolism of progesterone in vivo in the anesthetized female rhesus monkey during the follicular and luteal phases of the menstrual cycle.

Abstract

The in vivo metabolism of [3H]progesterone was studied in anesthetized female rhesus monkeys during either the early follicular phase or the midluteal phase of the menstrual cycle. An iv infusion of [3H]progesterone was given at a constant rate, and blood samples were obtained from catheters placed in the hepatic, renal, jugular, arm, and uterine veins and also in the femoral artery. The MCR of progesterone was 321 ± 14 (SE) liters/day. The MCR of progesterone in three dexamethasonetreated animals was 197 ± 15 (SE) liters/day. Tissue extractions of [3H]progesterone, calculated from the arteriovenous difference in blood concentrations, did not differ statistically between the follicular and luteal phases, except in the uterine extractions. The mean (±SE) extractions were: splanchnic, 94.5 ± 2.9%; renal, 14.6 ± 3.5%; head, 24.2 ± 1.5%; and arm, 48.1 ± 2.3%. The uterine extraction of progesterone was significantly (P = 0.001–0.005) higher in the early follicular phase [37.0 ± 7.8% (SE)] than in the luteal ph...