Biliary and Urinary Metabolites of Estriol-15-3H-3-sulfate-35S in Women1

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Abstract
Estriol-15-3H-3-sulfate-35S was synthesized and its metabolism was studied in 3 patients. In each patient the bile was being drained via a T-tube in the common duct following cholecystectomy. Following infusion of the doubly labeled estrogen, the conjugates excreted in the bile and urine were analyzed and compared. Virtually all the 3H and two thirds of the 35S were excreted within 24 hr, mostly in the first 6 hr. Only 9% of the 3H and 1.5% of the 35S (averages of 2 studies) were excreted in the bile in 24 hr. In one study, the conjugates excreted the first 6 hr were identified. Estriol-3-sulfate (E3S) and estriol-16-glucosiduronate (E3-16G) each comprised only 3% of the 3H excreted in the bile. Estriol-3-sulfate-16-glucosiduronate (E3SG) contained 75% of the biliary 3H and was virtually devoid of 38S. The 35S/3H ratio in E3S excreted the first 2 hr in the bile was similar to that perfused but was one half less at 2–6 hr. The urine contained the same conjugates but in different relative amounts: E3-16G (47%), E3S (22%) and E3SG (19%). The 35S/3H ratios were similar to those in bile at comparable times. These data suggest the following metabolic and excretory sequence for the infused E3S. Part was excreted in the bile and urine as such. Most of it was hydrolyzed and metabolized further. The major metabolite E3-16G was excreted mainly in the urine. Significant conversion of E3-16G to E3SG occurred. The latter was excreted partly in the urine but was the only conjugate excreted efficiently in the bile.