CHANGES IN ENZYMATIC ANTIOXIDANT ACTIVITY IN PREGNANT RATS EXPOSED TOHYPEROXIA OR HYPOXIA

Pregnant rats were exposed to chronic hyperoxia or hypoxia to examine whether endogenous (pregnancy) and external (exposure to environmental ) oxidative stresses have additive influences on inducing enzymatic an tioxidant activity (EAOA). The activities of catalase, glutathione per oxidase (GPx) and superoxide dismutase (SOD) were measured in the brai n, liver, lungs, heart, uterus and placenta in non-pregnant (N) and pr egnant (P) rats after 1 week of exposure to normoxia, hyperoxia and hy poxia. An additional combined effect in EAOA was found only in the hea rt. In the lungs and liver, EAOA increased both in pregnancy and hyper oxia, but no additive combined effect was noticed. The brain and N ute rus EAOA were not influenced by pregnancy or hyperoxia. In the placent a, only SOD and GPx activities increased. Hypoxia had a negligible eff ect on EAOA both in N and P rats. Generally, the EAOA response of P ra ts to environmental oxidative stress was higher than that of N rats. W e conclude that the influence of pregnancy and external oxidative stre ss on EAOA are not simply additive. (C) 1997 Elsevier Science Inc.