After a single intraperitoneal injection of 170-mu-mol nickel(II)acetate/kg body wt., the activity of hepatic catalase (CAT) decreased by 25-56% in a strain- and time-dependent manner, the most susceptible being C57BL/6NCr > C3H/HeNCr-MTV- > B6C3F1 greater-than-or-equal-to BALB/cAnNCr mice. The glutathione (GSH) levels in all 4 strains were inhibited by nickel with the C57BL/6NCr mice showing the biggest decrease (68%) followed by BALB/cAnNCr (46%) greater-than-or-equal-to B6C3F1 (42%) > C3H/HeNCr-MTV- (22%). The response of hepatic glutathione peroxidase (GSH-Px) to nickel was variable and included 30% enhancement in C3H/HeNCr-MTV- or lack of biologically significant effect (max. +/- 10% variations in time) in the remaining strains. The activity of glutathione reductase (GSSG-R) increased gradually by up to 30% (48 h post-injection) in B6C3F1 and C3H/HeNCr-MTV- mice or, transiently, by 15-18% (3 h), in C57BL/6NCr and BALB/cAnNCr mice. Also, in some strains, nickel significantly affected superoxide dismutase (SOD) (14-19% loss in C57BL/6NCr and B6C3F1 mice, respectively), and GSH-S-transferase (GST) (26% loss in C3H/HeNCr-MTV- mice). Lipid peroxidation (LPO) in the liver reached its highest value 24 h after nickel treatment in C57BL/6NCr (549% over the control) greater-than-or-equal-to BALB/cAnNCr (519%) > B6C3F1 (426%) >> C3H/HeNCr-MTV- (39%). In conclusion, the magnitude of nickel-induced LPO shows a reverse correlation with the extent and direction of nickel effect on GSH, GSH-Px and GSSG-R, but not on CAT, SOD or GST.