The metabolic fate of C14-progesterone in human subjects.

C14-progesterone was injected intravenously into 9 human subjects, 4 of whom had bile fistulas. In all subjects, slightly over 50 per cent of the radioactivity was excreted in the urine. At least 40 per cent of the urinary radioactivity was in the form of glucuronidates and over 60 per cent of the radioactive metabolites were extractable from the urine following all hydrolytic procedures. Nearly 30 per cent of the radioactivity was excreted in the bile, mostly as conjugates and metabolites not extractable following the various hydrolytic procedures. The amount of radioactivity excreted in the stools averaged 13 per cent and 3 per cent in the non-fistula and fistula subjects, respectively. The recovery of the total radioactivity in the urines and stools of the non-fistula subjects averaged 67 per cent, in contrast to the 82 per cent recovered in the urine, bile and feces of the bile-fistula subjects. These data are most consistent with substantial biliary excretion of metabolites of progesterone, consequen...