Arch Pharm (Weinheim). 1997 May;330(5):135-40.  

Influence of various estrogens on biotransformation: affinity to cytochrome
P-450, structure activity relationships, and scavenger function.

Gernhardt S, Karge E, Schonecker B, Klinger W.

Institut fur Pharmakologic und Toxikologie, Friedrich-Schiller-Universitat Jena,
Germany.

Nine natural and synthetic estrogens all derived from endogenous 17
beta-estradiol, were tested for their affinity to cytochrome P-450 (P450).
Binding spectra of the estrogens with rat liver microsomal P450 and inhibition
kinetics with characteristic monooxygenase model reactions (ethylmorphine
N-demethylation, EN, and ethoxycoumarin O-deethylation, EO) were determined. In
addition, uncoupling effects and/or free radical scavenger functions were
analysed by NADPH/Fe2+ stimulated microsomal luminol- and lucigenin-amplified
chemiluminescense (CL). 17 beta-Estradiol, 17 alpha-ethynylestradiol, and
D-estradiol 3-methyl ether inhibited both monooxygenase reactions of cytochrome
P-450, whereas L-estradiol 3-methyl ether inhibited EO only. 17 beta-Estradiol,
17 alpha-ethynylestradiol, and D-estradiol 3-methyl ether seem to act as free
radical scavengers. From the results both structure activity relationships could
be established and data on possible interferences with drug metabolism obtained.
The enantiomers D- and L-estradiol 3-methyl ether differ in their effects on
these systems.

PMID: 9237425 [PubMed - indexed for MEDLINE]