Effects of low-dose oral contraceptive oestrogen and progestin on lipid peroxidation in rats

Groups of six female rats were treated with low-dose oral contraceptive (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 lipid 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 lipid 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 ceruloplasmin decreased significantly when progestin was administered (P < 0.05). The activities of superoxide dismutase and catalase decreased significantly in the oestrogen group (except for catalase in the kidney) but increased 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.