Norethisterone, a Major Ingredient of Contraceptive Pills, Is a Suicide Inhibitor of Estrogen Biosynthesis
- 5 March 1982
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 215 (4537) , 1249-1251
- https://doi.org/10.1126/science.7058343
Abstract
Norethisterone (17 alpha-ethynyl-19-nortestosterone) is an effective irreversible inhibitor of estrogen synthetase (aromatase), the enzyme responsible for the conversion of androgens to estrogens, even at a 2 X 10(-6) molar concentration. This irreversible inactivation, which is directed toward the active site of aromatase and requires the cofactor-reduced nicotinamide adenine dinucleotide phosphate, is both time- and concentration-dependent. Ethisterone (17 alpha-ethynyltestosterone), in contrast, is not a suicide inhibitor of aromatase even at concentrations of 10(-4) molar.Keywords
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