URINARY-EXCRETION OF 6-BETA-HYDROXYCORTISOL IN WOMEN DURING TREATMENTWITH DIFFERENT ORAL-CONTRACEPTIVE FORMULATIONS

The measurement of the urinary excretion ratio of 6 beta-hydroxycortis ol (6 beta-OHC)/cortisol was used as a non-invasive method to investig ate possible changes in the activity of drug-metabolizing enzymes in w omen receiving different oral contraceptive formulations for 1 up to 3 treatment cycles. The contraceptive preparations were either levonorg estrel, gestodene or cyproterone acetate, each in combination with eth inyl estradiol, or only the progestogens levonorgestrel or gestodene. There was either no or only a small decrease in the 6 beta-OHC/cortiso l ratio. Thus, only a minor inhibitory effect, if any, can be ascribed to the investigated contraceptive steroids in vivo. Previously observ ed differences between selected contraceptive steroids in vitro were n ot observed in the same way in vivo. This may be due either to the abs ence of a marked inhibitory activity in vivo or to the insufficient se nsitivity of the marker 6 beta-OHC/cortisol to detect these changes. A nother possible reason may be the considerably higher drug concentrati ons used in the in vitro studies as compared to those present in the s erum of women under oral contraceptive therapy.