Formation of Estrogen Glucosiduronates by Human Kidney Homogenates

Abstract

17β-Estradiol-6,7-3H (E2), 17β-estradiol-6,7-3H-3-sulfate (E23S), and estriol-6,7-3H (E3) were each incubated with human kidney homogenates in the presence of uridine diphosphoglucuronic acid. Metabolites were purified by DEAE-Sephadex and Celite partition chromatography and were identified by crystallization with carrier steroid conjugates and free steroids. E2 was converted to a small but definite extent (< 0.1–5%) to estrone-3-glucosiduronate, 17β-estradiol-3-glucosiduronate, and 17β-estradiol-17-glucosiduronate, the latter conjugate usually predominating. Under the experimental conditions E2 was a better precursor of all three conjugates than was E23S. In one experiment where kidney cortex and medulla were incubated separately with E2, the former was some 20 times more efficient in glucosiduronate synthesis. E3 was converted to the extent of 52–91% to estriol-16-glucosiduronate by whole kidney homogenates.