Comp. Biochem. Physiol. Vol. 73B, No. 4, pp. 945 to 949, 1982 0305-0491/82/120945-05503.00 0 Printed in Great Britain. © 1982 Pergamon Press Ltd GLUTATHIONE PEROXIDASE ACTIVITIES OF ANIMAL TISSUES MARY E. TAPPEL, JEAN CHAUDIERE and ALL. TAPPEL Department of Food Science and Technology, University of California, Davis, CA 95616, USA (Received 4 May 1982) Abstract--1. Selenium-dependent, selenium-independent and total glutathione peroxidase activities were measured in liver, kidney, heart, lung, intestine and stomach of a variety of animals, mostly mammals. 2. Total glutathione peroxidase activity of liver was highest in the order: hamster > gerbil ~ rab- bit > mouse > rat. Total glutathione peroxidase activity was adequate in the livers of other mammals and in the kidney, heart, lung, intestine and stomach of all mammals. 3. The total glutathione peroxidase activities in the following tissues correlated significantly: liver and kidney; heart and lung; and intestine and stomach. Selenium-dependent glutathione peroxidase activities in rat tissues correlated with reported activities of copper-superoxide dismutase in the same tissues. 4. Considering the phylogenetic distribution of total glutathione peroxidase activities, the rodent limb of the phylogenetic tree has the highest activities. INTRODUCTION Glutathione peroxidase activities of animal tissues are accounted for by a selenocysteine-containing gluta- thione peroxidase (E.C. 1.11.1.9) and a selenium-inde- pendent glutathione peroxidase. In the liver, the latter activity is believed to arise from a side reactivity of glutathione-S-transferase (Prohaska & Ganther, 1977; Pierce & Tappel, 1978; Prohaska, 1980). Through reduction of hydrogen peroxide, lipid hydroperoxides and other organic hydroperoxides, the glutathione peroxidase systems provide protection against oxida- tive damage and accumulation of free-radical products (Tappel, 1981). In rat tissues, with the excep- tion of testes, most of the glutathione peroxidase ac- tivity is due to the selenoenzyme (Lawrence & Burk, 1978). Among these tissues, liver and kidney have high glutathione peroxidase activities as well as a high selenium content, about 400 and 1000ng/g of fresh tissue, respectively (Chow & Jeng, 1981). Little infor- mation is available for species other than the rat, however. One value of making comparative studies is that they allow a search of common patterns of enzyme distribution. Any general pattern of gluta- thione peroxidase distribution would presumably pro- mote an understanding of its biological function, es- pecially if this distribution could be correlated with the distribution of another enzyme(s) and/or meta- bolic cofactor(s). Another value of making compara- tive studies is that animal and tissue sources with high glutathione peroxidase activity can be identified. There are obvious advantages to using a source of glutathione peroxidase of high activity as the starting material for purification of selenium glutathione per- oxidase to be used in biochemical studies. Heretofore, most studies have focused on a single animal species. Only a small survey of glutathione peroxidase has been reported, mainly on blood and muscle (Smith & Shrift, 1979). The data obtained in different labora- tories on glutathione peroxidase activities are expressed in various units and are difficult to recon- cile; this shows the need for a systematic survey based on a single methodology. Selenium-glutathione per- oxidase of the cytosol fraction of rat liver and lung has been characterized (Chiu et al., 1976; Stults et al., 1977; Forstrom et al., 1979). Our knowledge of these characterized enzymes, their substrate needs and mode of assay justifies the choice of a glutathione reductase-coupled assay of the cytosolic glutathione peroxidase activity of other animal tissues. MATERIALS AND METHODS Anhnals or tissues Live animals or fresh tissues were obtained at least in triplicate from the following sources: gerbils (Meriones unyaiculatus) and white leghorn chickens (Gallus domes- ticus), University of California, Davis; mice (Mus museulus), rats (Rattus Norve(licus), Hartley guinea-pigs (Cat:ia por- cellus) and golden hamsters (Mesoericetus auratus), Simon- sen Laboratories, Inc. (Gilroy, CA); rabbits (Oryetola~,lUS euniculus), local rabbit breeders; rainbow trout (Salmo .qairdneri) and brook trout (Salvelinusfimtinalis). a local fish hatchery; wild house mice (Mus musculus), California ground squirrels (Citellus rarieyatus), Western fence lizard (Sceloporus oceidentalis), American toad (Bt{[o terrestris americanus), Western newt (Tarieha torosa), carp (C yprim~s carpio) and blue gill sunfish (Lepomis macrochirus), by live trapping or catching; cow (Bos taurus) and sheep (Ovis aries) tissues, local slaughterhouse; and cat (Felis catus) and dog (Canisfamiliaris) tissues, a local animal shelter. The animals or tissues in each group were obtained from the same sources, were of the same age and sex, and had access to the same diet insofar as possible. Preparation of eytosol.fi'actions jbr study ~)[' total ~llutathione peroxidase actirity The tissues were removed from the animals and placed on ice immediately after the animals were killed. Within a few hours of dissection, the tissues were minced and homo- nogenized 1:7 (w:v) in 0.25 M sucrose in a glass and Teflon homogenizer. A Waring blendor was used for tough tissues such as stomach and heart. Tissue cytosoI fractions were prepared by centrifugation at 4C for 15 rain at 13,000.q 945