The metabolism of equilin in normal men.
Healthy adult males received either [3H]-equilin intravenously (one subject) or a larger mass of unlabelled equilin orally (three subjects). Blood samples were taken at 20, 40, 60, 90 and 120 min and every h thereafter until eight h after injection. Urine was collected in 24 h aliquots for five days from all subjects. The half-life of the disappearance of the unconjugated radioactivity from blood was 30 min and that in the conjugated sulfate fraction was 5 1/2 h. Approximately 50% of the injected radioactivity was recovered in the urine over 5 days. After extraction, hydrolysis and fractionation, most (83%) of the radioactive material found in the urine was present in the glucuronide fraction while only 2 and 6% were present in the unconjugated and sulfate fractions, respectively. The three fractions were combined for further isolation and identification of the metabolites. Radiochemically pure equilin, equilenin, 17 beta-dihydro-equilin and 17 beta-dihydroequilenin were isolated and identified but the largest fraction of radioactivity (70.5%) was present in the form of metabolites which are more polar than any of the known ring B unsaturated estrogens. These appear to be polyhydroxy 17-reduced ring B unsaturated estrogens. These results indicate that the ring B unsaturated estrogen equilin is being metabolized in man in a somewhat similar manner to that of the classical estrogen estrone. Knowledge of the formation of 17 beta-dihydroequilin from equilin in man is of importance because this estrogen is approximately 8 times more potent as a uterotrophic agent than the commonly used estrogen, equilin.
D015068:17-Ketosteroids / Q000097:blood*; D000284:Administration, Oral; D000328:Adult; D004857:Equilin / Q000008:administration & dosage / Q000097:blood* / Q000652:urine; D006801:Humans; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D014316:Tritium
D015068:17-Ketosteroids; D004857:Equilin; D014316:Tritium