Metabolism of Oestrone and Oestradiol-17β in Human Liver in vitro

Abstract

SINCE the discovery of the so-called “newer” oestrogens by Marrian et al. and by Gallagher and Fishman et al.¹, much work has been directed towards an explanation of their intermediary metabolism in human liver tissue². In contrast, little information is available on the metabolism of the three “classical” oestrogens—oestrone, oestradiol-17β and oestriol—in human liver in vitro. Thus, Ryan and Engel³ found a reversible transmutation of oestrone and oestradiol-17β in human liver tissue slices; Engel et al.⁴ reported the formation of oestriol, 16-epi-oestriol and oestrone after incubation of oestradiol-17β by human foetal liver, and Breuer et al.⁵, using a similar system, identified 6-hydroxyoestradiol-17β and oestriol as metabolites of oestradiol-17β. In view of the significance of oestrone and oestradiol-17β as precursors of the “newer” oestrogens, it seemed that a more intensive search for the metabolites of the two oestrogens in human liver tissue was justified. Accordingly, the present investigation was undertaken.