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Exp Clin Endocrinol Diabetes 1994; 102(5): 388-393
DOI: 10.1055/s-0029-1211309
Original

© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Characterization of estrone hydroxylase activities in porcine endometrial cells

J. Adamski, Elke Hohls1 , P. W. Jungblut
  • Max-Planck-Institut für experimentelle Endokrinologie, Hannover, Germany
1 Contains part of the Ph. D. thesis of E. H., University Hannover, 1991
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Publication History

Publication Date:
15 July 2009 (online)

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Summary

The oxidation of estradiol to estrone in porcine endometrial cells is succeeded by hydroxylation at either 6α- or 7α-. The products are devoid of receptor affinity. Their formation is inhibited by cytochrome P450 blockers like ketoconazol but not by chloroquine and analogues. The hydroxylation at 6α- proceeds with KM = 1.9 × 10−7 M, that at 7α- with KM = 3.6 × 10−7 M. The respective values for the cytochrome P450-reductase cosubstrate NADPH are 1.7 × 10−5 M and 1.9 × 10−5 M. The kinetic parameters of the enzymes are compatible with a metabolic sequence: estradiol → estrone → 6α-/7α-estrone.

Key words

Estrone hydroxylation - inhibition - kinetics - P450-enzymes

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