M. Maracine et H. Segner, CYTOTOXICITY OF METALS IN ISOLATED FISH CELLS - IMPORTANCE OF THE CELLULAR GLUTATHIONE STATUS, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 120(1), 1998, pp. 83-88
The study investigates the importance of glutathione (GSH) for protect
ion of fish cells against heavy metal stress. The cytotoxicities of si
x metal salts to the continuous rainbow trout cell line RTG-2 were det
ermined by means of the neutral red (NR) uptake inhibition assay. The
rank order of metal cytotoxicities (in terms of NR50 values) were Hg >
Cd > Zn > Cu > Pb > Ni. The importance of GSH in determining metal to
xicity was assessed by inhibition of its synthesis. A 20 h pretreatmen
t of RTG-2 cells with 1 mM buthionine sulfoxime caused sustained reduc
tion of cellular GSH level to approximate to 30% of the control value.
The effect of GSH depletion on metal cytotoxicity was found to be rel
ated to the chemical softness parameter of the metal cations: Cytotoxi
cities of the 'soft' metals Hg, Cu and Cd were significantly increased
in GSH-depleted cells, whereas cytotoxicities of the 'hard' metals Zn
, Ni and Pb were not significantly altered. Since chemical softness is
a determinant for binding of metal ions to sulfhydryl groups as being
present in GSH, the findings of this study suggest that the metal-pro
tective effect of GSH in fish cells is, at least partly, due to its ac
tion as an intracellular metal chelator; (C) 1998 Elsevier Science Inc
. All rights reserved.