Selenium and glutathione peroxidase activity in blood of the nutria ( Myocastor coypus): Comparison with guinea-pig, rat, rabbit and some non-mammalian vertebrates

Abstract

1. 1. Plasma selenium and selenium-dependent glutathione peroxidase (GSH-Px) activity in plasma and erythrocytes were measured in the nutria ( Myocastor coypus) and the alligator ( Alligator mississippiensis). Plasma and erythrocyte GSH-Px activity only were measured in the rat, rabbit, chicken, quail, turtle ( Chrysemys picta), snake ( Nerodia fasciata), bullfrog ( Rana catesbiana) and catfish ( Ictalurus punctatus). 2. 2. Plasma GSH-Px activity ranged from a low of 0.021 EU/ml in the bullfrog to a high of 1.97 EU/ml in the alligator. 3. 3. Erythrocyte GSH-Px activity was lower in the nutria (2.8 EU/g Hb) than all other species studied. Whereas the rat had the highest activity (539 EU/g Hb). The variation among the mammalian species studied was greater than between the different orders of vertebrates. There was no relationship between plasma and erythrocyte GSH-Px activity and no phylogenetic pattern in the differences in activity between species. 4. 4. There was a relationship between plasma selenium concentration and enzyme activity: animals with the lowest enzyme activity had lowest selenium levels.