Effect of contraceptive pills on the activity status of the antioxidant enzymes glutathione peroxidase and superoxide dismutase in healthy subjects.

BACKGROUND

Experimental evidences suggest that metabolic activation and conversion of oral contraceptive pills (OCPs) to reactive species are responsible for their genotoxicity. The present study was undertaken to investigate the effects of low-dose (LD) OCPs on the activities of erythrocyte antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD) in OCP consumers.

STUDY DESIGN

Enzyme activities were assayed spectrophotometrically in 50 healthy women with normal menstrual cycles who served as the control group and 50 women taking LD OCPs.

RESULTS

The pooled data obtained for erythrocyte GPX activity in OCP consumers (50.05 ± 14.9 U/g of Hb) was significantly higher (+15.4%, p = .015) than in the control group (42.33 ± 16.31 U/g of Hb), but the same comparison for SOD activity between the control group (83.46 ± 23.97 U/g of Hb) and women receiving OCPs (81.83 ± 23.97 U/g of Hb) showed an insignificant (-2%, p = .699) decrease. The duration of intake of OCPs beyond 36 months had an effect on the magnitude of the increase (+16.2%) and the decrease (-11%) in GPx and SOD activities, respectively. There was a significant and considerable (not significant) correlation between the activities of GPx (p = .039) and SOD (p = .102) with the duration of OCP consumption, respectively.

CONCLUSION

These findings suggested that OCPs may stimulate or reduce the activities of GPx and SOD enzymes, respectively. This may be due to an effect of these pills on bone marrow erythroblast maturation via stimulation or inhibition of the synthesis of new active GPx and SOD molecules or may be a result of the increased frequency of an allele of the GPx and SOD enzymes. It is suggested that these alterations in GPx and SOD activities may be related to their probable protective effects in response to various pathological and physiological properties of OCPs. It seems that probably free radicals produced during metabolism of OCPs provoke the activity of antioxidant enzymes.