Effect of rifampicin treatment on the metabolism of oestradiol and 17alpha-ethinyloestradiol by human liver microsomes.

摘要: Liver biopsies were obtained from four patients treated with rifampicin 600 mg for 6–10 days. Hepatic microsomes incubated an NADPH-regenerating system and the substrates [2, 4, 6, 7--3H] oestradiol, [6, 7-3H] ethinyloestradiol ethinyloestradiol. The hydroxylation rates of these steroids at labelled positions rings A B determined by measuring transformation tritium into HTO microsomal enzymes. Comparison previously published data showed that treatment caused a fourfold increase in rate oestradiol C-2/C-4 ring C-6/C-7 B. acceleration oestrogen was paralleled cytochrome P-450, also reduction rifampicin-quinone, reactive metabolite rifampicin. increased aromatic leads to enhancement their irreversible binding protein. provide explanation diminished efficacy oestrogens contraceptive formulations given under