EFFECTS OF LOW-DOSE ORAL-CONTRACEPTIVE ESTROGEN AND PROGESTIN ON LIPID-PEROXIDATION IN RATS

Groups of six female rats were treated with low-dose oral contraceptiv e (0.667 mg progestin [norethisterone acetate] and 0.02 mg oestrogen [ ethinyloestradiol]/kg body-weight), or its components, separately, at the same doses, for 6 weeks. Changes in liver and kidney levels of lip id peroxides (as indicated by malondialdehyde production), free fatty acids, superoxide dismutase, and catalase liver glutathione and serum ceruloplasmin compared with the untreated control group were studied. Combined oral contraceptive treatment produced a significant increase in the activity of catalase in the kidneys (P < 0.05). The levels of l ipid peroxides, free fatty acids and glutathione in the liver, and of serum ceruloplasmin increased significantly with oestrogen treatment ( P < 0.05). Lipid peroxides (in the liver only), and serum ceruloplasmi n decreased significantly when progestin was administered IP < 0.05). The activities of superoxide dismutase and catalase decreased signific antly in the oestrogen group (except for catalase in the kidney) but i ncreased in the progestin group (P < 0.05). The results indicate that the components of the low-dose oral contraceptive may alter liver and kidney metabolism.