Antioxidant levels from different Antarctic fish caught around South Georgia’s Islands and Shag Rocks.

ANSALDO M, LUQUET, C; EVELSON, P; POLO, J; LLESUY S.

POLAR BIOLOGY

Springer

Lugar: Heidelberg; Año: 2000 vol. 23 p. 160 - 165

0722-4060

Abstract Antarctic ®sh have been isolated for over several million years in an environment with a very low and constant temperature and high oxygen concentra- tion. In such conditions the oxidative stress might be an important factor a.ecting their metabolic adaptive strategies. Activity of the antioxidant enzymes super- oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), vitamin E levels and total antioxidant capacity (TRAP) were measured in liver, gill, heart and muscle homogenates of red-blooded (Nototheniidae) and white-blooded (Channichthyidae) Antarctic ®sh. SOD activity was also measured in blood samples. Gill SOD activity was threefold higher in channichthyids than in nototheniids while CAT and GPx were signi®- cantly higher in the gills of channichthyids. The in- creased SOD activity of channichthyids probably re¯ects the large PO2 gradient across their gills. The H2O2Antarctic ®sh have been isolated for over several million years in an environment with a very low and constant temperature and high oxygen concentra- tion. In such conditions the oxidative stress might be an important factor a.ecting their metabolic adaptive strategies. Activity of the antioxidant enzymes super- oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), vitamin E levels and total antioxidant capacity (TRAP) were measured in liver, gill, heart and muscle homogenates of red-blooded (Nototheniidae) and white-blooded (Channichthyidae) Antarctic ®sh. SOD activity was also measured in blood samples. Gill SOD activity was threefold higher in channichthyids than in nototheniids while CAT and GPx were signi®- cantly higher in the gills of channichthyids. The in- creased SOD activity of channichthyids probably re¯ects the large PO2 gradient across their gills. The H2O22 gradient across their gills. The H2O2 produced seems to be preferentially eliminated by dif- fusion, according to the low levels of CAT and GPx found in the gills of these species. In contrast, blood SOD was about ®vefold higher in the latter group, which possesses erythrocytes and thus a much higher oxygen- carrying capacity. CAT activity was always higher in nototheniids except in muscle. However, vitamin E did not show clear di.erences between families except for the pattern observed in muscle. The higher content of vitamin E in this tissue shown in channichthyids is related to the higher volume density of mitochondria reported for this group, since vitamin E is responsible for preventing membrane lipid peroxidation. Accord- ingly, TRAP (representative of hydrosoluble antioxidant capacity) was also higher in muscle of channichthyids. This is probably related to the role of ascorbic (a hydrosoluble compound) acid in regenerating vitamin E.