Observations on progesterone production and clearance in normal pregnant and fetectomized rhesus monkeys (Macaca mulatta).

The metabolic clearance rate (MCR) and production rate (PR) of progesterone were measured in rhesus monkeys both before and during intravenous infusion of progesterone at rates which approximately doubled or tripled the peripheral plasma levels. The monkeys were normally pregnant or fetectomized and were studied during the second half of pregnancy. Raising the peripheral plasma levels did not significantly after the MCR or the PR of progesterone. We conclude that peripheral progesterone levels are not the factor which controls the PR of progesterone in rhesus monkeys.