Contraceptive steroids increase erythrocyte lipid peroxidation in female rats.

In order to investigate the effects of contraceptive steroid combinations on lipid peroxidation in the erythrocyte membranes, adult female rats were divided into 2 groups for short- and long-term investigations; each group was then subdivided into 5 subgroups according to orally given low and high doses of EE/NEA (ethinyl estradiol/norethisterone acetate) and EE/LNG (ethinyl estradiol/levonorgestrel) combinations and control group. Since EE was included in each combination, the groups were named according to the progestin (NEA, LNG) components. At the end of the experiment periods, lipid peroxidation in the erythrocyte membranes from rats was measured. When compared to the controls, except low-dose LNG groups, lipid peroxidation levels were increased in all study groups. It was seen that the effect of NEA and LNG combinations on lipid peroxidation was not time-, but dose-dependent. When these combinations were compared to each other, different effects of NEA and LNG on lipid peroxidation were not detected in the experiment period. As a result, the increased lipid peroxidation following the administration of contraceptive steroid combinations is a very important finding that should be taken into account, in addition to the effects of these steroids on lipid and lipoprotein metabolism.