Sex- and age-dependent activity of glutathione peroxidase in reproductive organs in pre- and post-pubertal cattle in relation to total antioxidant capacity.

Antioxidative/oxidative balance is crucial for proper functioning of cells and tissues. It is suggested that this balance can be partly controlled by sex steroid hormones and in consequence can exhibit age- and sex-related dependency. The aim of present study was to describe sex- and age-related changes in the activity of glutathione peroxidase (GSH-Px) with respect to total antioxidant activity (TAC) in reproductive organs of cattle. Biological samples were collected from slaughterhouse and comprised of ovaries, uterus, testes as well as livers as reference tissue. Animals were divided into group of bulls (aged between 13 and 24 months; n = 12), cows (aged between 14 and 27 months; n = 12) and female calves (aged between 2 weeks and 2 months; n = 12). Examined parameters were determined spectrophotometrically and the presence of GSH-Px isoform was confirmed by Western blotting technique. Activity of GSH-Px in genital tissues regardless of sex was significantly higher than in livers, while TAC showed opposite relationship. The differences in antioxidative parameters between testes and mature ovaries (e.g. GSH-Px-1.42 ± 0.47 nkat/mg prot vs. 1.08 ± 0.24 and 1.15 ± 0.23) were noticed as well as in chosen values between cows and female calves. Western blotting allowed the detection of cytosolic GSH-Px in all examined tissues with molecular weight around 21 kDa as monomer and around 84 kDa as tetramer depending on conditions of electrophoresis. The results may confirm the influence and regulatory role of sex steroid hormones on GSH-Px activity because the alterations were sex and age dependent.