Estradiol 17.BETA.-sulfate as a substrate for 2-hydroxylation enzyme of rat liver microsomes. (clinical analysis on steroids. XX).

Publisher Website
Google Scholar
Abstract
4-14 C-Estradiol and its 17.beta.-sulfate were incubated with rat liver microsomes under NADPH-generating system. Estradiol in liver microsomes from male and female rats was metabolized to multiple kinds of oxidized products including estrone, 2-hydroxyestrone, 2-hydroxyestradiol and other minor steroids. Incubation of estradiol 17.beta.-sulfate was carried out by the same condition, and the metabolic pattern between male and female rats was different. By incubation of estradiol 17.beta.-sulfate with male rat liver microsomes, 2-hydroxyestradiol 17.beta.-sulfate was obtained as the sole product (6%). The hydroxylation occurred without cleavage of the conjugate group. No such regulating effect by conjugate group on 2-hydroxylation of estradiol 17.beta.-sulfate was observed in liver microsomes from female rats. The amount of 2-hydroxyestradiol 17.beta.-sulfate formed was only 1%, and monohydroxylated estradiols were produced as the major products. The 2-hydroxylated metabolite of estradiol 17.beta.-sulfate was confirmed by its isolation as a stable form of derivative by the following method: the incubation mixture of massive amounts of estradiol 17.beta.-sulfate was extracted with n-butanol; methylation of the extract with diazomethane, followed by acid-catalyzed hydrolysis, acetylation and, finally, separation by preparative TLC, gave a crystalline material, the spectral properties of which were completely identical with those of the synthetic specimen, 2,3-dimethoxy-1,3,5(10)-estratrien-17.beta.-yl acetate.