Formation of Estrogen Glucosiduronates by Human Kidney Homogenates

Abstract

17β-Estradiol-6,7- 3 H (E 2 ), 17β-estradiol-6,7- 3 H-3-sulfate (E 2 3S), and estriol-6,7- 3 H (E 3 ) 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. E 2 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 E 2 was a better precursor of all three conjugates than was E 2 3S. In one experiment where kidney cortex and medulla were incubated separately with E 2 , the former was some 20 times more efficient in glucosiduronate synthesis. E 3 was converted to the extent of 52–91% to estriol-16-glucosiduronate by whole kidney homogenates.