Metabolism of estrone-3-glucosiduronate and 17 β-estradiol-3-glucosiduronate in the human female

Abstract

Estrone-6,7- 3H-3-glucosiduronate- 14C ( 3H-E 1 3G- 14C) and 17 β-estradiol-6,7- 3H-3-glucosiduronate- 14C ( 3H-E 2 3G- 14C), both of 3H/ 14C ratio = 5.8, were each injected into two normal young females. Seventy percent of each isotope was excreted in the urine in 3 hr, and at 48 hr, when excretion of the radioactivity had ceased, some 90% of 3H and 75% of 14C had been excreted. Urinary metabolites were purified and identified by Amberlite XAD-2 resin, DEAE-Sephadex and Celite partition chromatography followed by derivative formation, enzymic hydrolysis and crystallization with carrier steroids. No urinary metabolites other than E 1 3G and E 2 3G were identified. Within 3 hr of injection direct interconversion of E 1 3G and E 2 3G was observed as reflected in the 3H/ 14C ratios of the urinary metabolites which were the same as that injected. Under the experimental conditions the conversion, E 2 3G → E 1 3G, was much greater than the reverse. From 3 to 6 hr after injection the urinary metabolites possessed higher 3H/ 14C ratios (7.1 – 13.5) than that injected, indicating partial deconjugation to have taken place. From 6 to 24 hr after injection no 14C could be detected with certainty to be associated with the 3H-metabolites, showing that the latter had been produced through a process of initial deconjugation, followed by reconjugation with glucuronic acid of endogenous origin.