EFFECTS OF ATENOLOL, LABETALOL AND METHYLDOPA ON ENDOGENOUS ANTIOXIDANTS IN-VITRO

The aim of this study was to investigate whether atenolol, labetalol a nd methyldopa, which are commonly used for the treatment of hypertensi on in pregnancy, can induce antioxidant activity. Reactive oxygen spec ies scavengers (plasma thiol, red cell lysate thiol, red cell superoxi de dismutase, red cell membrane thiol and plasma glutathione) were mea sured after incubation of peripheral blood with atenolol and methyldop a, respectively. The results showed that atenolol and labetalol could significantly raise the levels of plasma thiol and membrane thiol but had no effects on lysate thiol, superoxide dismutase and glutathione. The effects on membrane thiol occurred after 60 min incubation and on plasma thiol after 120 min incubation. The data also suggest that aten olol and labetalol at lower concentrations tend to have additive effec ts on reactive oxygen species scavengers but at higher concentrations do not. Methyldopa had no significant effect on any of the parameters measured. These findings suggest that atenolol and labetalol are able to induce higher levels of antioxidant activity.