Modulation of selenium-dependent glutathione peroxidase (Se-GSH-Px) activity in mice

Selenium-dependent glutathione peroxidase activity was assessed in the liver, kidney, lung and blood of mice from seven strains (129/ReJ, BALB/c, C3H/HeSnJ, C3H/S, C57BL/6J, Csb, and S.W.) at five ages (newborn, 21, 70, 175 and +500 days old). Activity was highest in the liver (0.25 U/mg protein) followed by blood hemolysate (0.16 U/mg protein) with kidney and lung displaying similar, comparatively lower levels of activity (0.14 and 0.12 U/mg protein respectively). Although activity was shown by statistical analysis to be not significantly different among the strains (p = 0.05), age-associated, strain-specific changes in enzyme activity were noted to be highly significant (p = 0.001). Also, ethanol administered in drinking water resulted in a marked reduction in selenium-dependent glutathione peroxidase activity during both short- (1-2 weeks) and long- (5-6 weeks) term treatment periods. Changes in this enzyme due to aging and after exposure to xenobiotics such as ethanol may have serious ramifications given the importance of this enzyme in the detoxification of reactive oxygen metabolites.