The in vitro metabolism of ethinyloestradiol, mestranol and levonorgestrel by human jejunal mucosa.

Abstract

1 Ethinyloestradiol was extensively metabolised in vitro by human jejunal mucosa to form ethinyloestradiol sulphate. 2 The amount of conjugation was directly related to the weight of biopsy tissue. 3 The degree of conjugation of mestranol and levonorgestrel was much lower than for ethinyloestradiol suggesting that the 17-position of the steroid nucleus is relatively inaccessible for conjugation. 4 No Phase I metabolism of ethinyloestradiol or levonorgestrel was apparent in the conditions used in these experiments.