EFFECT OF CONTRACEPTIVE AGENTS ON DRUG METABOLISM

A series of steroids including progesterone, medroxyprogesterone, norethynodrel, estrone, mestranol and ethynylestradiol have been administered either acutely of chronically, alone or in combination, to rats to test for possible effects on drug metabolism. Two hours after norethynodrel (50 mg/kg, oral) the sleeping time produced by pentobarbital was prolonged due to an increase in the level of brain pentobarbital. Medroxyprogesterone (10 mg/kg) either alone or combined with ethynylestradiol (0.018 mg/kg) and norethynodrel (10 mg/kg) combined with mestranol (0.018 mg/kg) given orally for 30 days decreased the level of brain pentobarbiral without affecting pentobarbital narcosis. Medroxy progesterone alone or combined with ethynylestradiol in the same experimental conditions increased the metabol of p-nitroanisol, aminopyrine and aniline in vitro (liver 9000 × g supernatant).{A table is presented}. © 1969.