Regulation of antioxidant enzyme activities in male and female rat macrophages by sex steroids

Abstract

Human and animal immune functions present sex dimorphism that seems to be mainly regulated by sex hormones. In the present study, the activities of the antioxidant enzymes total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were measured in intraperitoneal resident macrophages from adult male and female rats. In addition to comparing males and females, we also examined the regulation of these enzyme activities in macrophages by sex steroids. GSH-Px activity did not differ between male and female macrophages. However, both total SOD and CAT activities were markedly higher in females than in males (83 and 180%). Removal of the gonads in both males and females (comparison between castrated groups) increased the difference in SOD activity from 83 to 138% and reduced the difference in CAT activity from 180 to 86%. Castration and testosterone administration did not significantly modify the activities of the antioxidant enzymes in male macrophages. Ovariectomy did not affect SOD or GSH-Px activity but markedly reduced (48%) CAT activity. This latter change was fully reversed by estrogen administration, whereas progesterone had a smaller effect. These results led us to conclude that differences in the SOD and CAT activities may partially explain some of the differences in immune function reported for males and females. Also, estrogen is a potent regulator of CAT in macrophages and therefore this enzyme activity in macrophages may vary considerably during the menstrual cycle.

Gender difference in the development of cardiac lesions following acute ischemic-reperfusion renal injury in albino rats

“…The higher level of cardiac CAT in females than in males reported in this study could be explained by the increased activity of SOD which catalyzes the dismutation of O 2 • -into O 2 and H 2 O 2 ; the accumulating H 2 O 2 induces the expression of CAT (Röhrdanz and Kahl 1998). Azevedo et al (2001) reported that CAT level in macrophages was significantly higher in female rats than in males, and ovariectomy led to significant reduction in its level. Massafra et al (1997), as well, found that females receiving oral contraceptives showed a significant increase in the serum CAT level, indicating that sex steroids may have an antioxidant activity mediated by CAT induction.…”

Estrogen suppresses brain mitochondrial oxidative stress in female and male rats

“…MnSOD protein levels are, however, only one index of superoxide metabolism; evidence suggests MnSOD activity may be regulated as well (Azevedo et al, 2001;Pedram et al, 2006;Strehlow et al, 2003). Interestingly, estrogen enhanced MnSOD activity in both female and male brains, while testosterone and DHT had no effect.…”

“…For example, in female rats, brain mitochondrial peroxide production was lower than in mitochondria from male rats (Borras et al, 2003). Physiologic concentrations of estrogen can also protect against oxidative damage through modulation of antioxidant enzyme activity, including superoxide dismutase, catalase, and glutathione peroxidase (Azevedo et al, 2001;Murakoshi et al, 1999).…”

The modulatory effect of estradiol benzoate on superoxide dismutase activity in the developing rat brain

“…Data suggest that estradiol contributes to the physiological modulation of these enzymes in various tissues of rats and humans. It has been shown that erythrocyte GPx activity is higher in women than in men (1), and that the activities of SOD and GPx in liver (2) and SOD and CAT activities in macrophages (3) are significantly higher in female rats. The luteal content of SOD changes during the S. Peji et al ovulatory cycle in humans (4), whereas GPx activity in erythrocytes is positively correlated with plasma estradiol levels during the menstrual cycle (5).…”