Effect of sex and time of sampling on selenium and glutathione peroxidase activity in tissues of mature rats.
Sprague-Dawley rats were used to investigate variations in measures of glutathione peroxidase (GSH-Px) and selenium (Se) concentration resulting from diurnal cycles and sex. Mature rats (equal numbers of males and females) were killed at 4 h intervals over a 48 h period (0200, 0600, 1000, 1800 and 2200 h each day). Selenium and GSH-Px were measured in plasma, erythrocytes, and liver and kidney cytosols. Selenium concentrations did not vary diurnally, but plasma GSH-Px activities were higher during the light than dark periods. Males had greater plasma GSH-Px activities and Se concentrations (42 EU and .45 mg/kg, respectively) than females (35 EU and .41 mg/kg respectively). GSH-Px activities were also higher in male kidney cytosols than females (117 and 76 EU, respectively). Selenium and GSH-Px activities, however, were lower in male liver cytosols (.48 mg/kg and 272 EU) than females (1.19 mg/kg and 795 EU, respectively). These data suggest that Se is distributed differently in male and female rats and the difference in Se distribution is accomplished by differences in GSH-Px activities.
Finley
J W
JW
Animal Sciences Department, Washington State University, Pullman 99164-6320.
Kincaid
R L
RL
D000818:Animals; D002940:Circadian Rhythm; D003600:Cytosol / Q000201:enzymology; D003624:Darkness; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008027:Light; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012643:Selenium / Q000097:blood / Q000378:metabolism*; D012727:Sex Characteristics
D005979:Glutathione Peroxidase; D012643:Selenium