Glutathione redox system, GSH-Px activity and lipid peroxidation (LPO) levels in tadpoles of R.r.ridibunda and B-viridis

Total glutathione (t-GSH), reduced glutathione (GSH), glutathione disulphide (GSSG) levels, t-GSHIGSSG ratio, glutathione peroxidase (GSH-Px) activity and lipid peroxidation (LPO) levels were investigated during the development period of a predominantly aquatic amphibian R.r.ridibunda and a predominantly terrestrial amphibian B. viridis. While t-GSH and GSH showed a similar trend, GSSG concentration increased significantly (p < 0.05) during the larval stages in R.r.ridibunda larvae. In contrast to R. r ridibunda larvae, there was no significant (p > 0.05) change between I and 5 weeks in the t-GSH and GSH concentrations of B. viridis. t-GSH and GSH concentrations of B. viridis larvae became sharply elevated after the fifth week, GSSG levels increased 3.25-fold during the metamorphosis. The t-GSH/GSSG ratio fluctuated and the lowest t-GSH/GSSG ratios were observed at the third week for both species. GSH-Px activities for both species increased significantly (p < 0.05) during the growing period. The highest GSH-Px activities in R.r.ridibunda and R.viridis were observed at the eighth week and they were 3.45 +/- 0.17 and 4.1 +/- 0.21 IU mg(-1), respectively. The membrane LPO levels in the R.r.ridibunda and B. viridis tadpoles significantly (p < 0.001) decreased from 206 +/- 10.3 to 146 +/- 7.3 and from 198 +/- 9.9 to 23 +/- 1.15 nmol MDA g(-1) w.w., respectively. Copyright (C) 2002 John Wiley Sons, Ltd.