Accumulation of hepatic Hsp70 and plasma cortisol in Oreochromis mossambicus following sublethal metal and DDT exposure

Abstract

Heat shock response in Oreochromis mossambicus livers was measured, using antibodies specific to Hsp70 family members, by an immunoblotting protocol. The hepatic isoforms Hsp70, Hsp74 and Hsp76 were identified and quantified from copper exposures. Long-term DDT exposure did not result in significant induction of hepatic Hsp70. An increase in plasma cortisol concentration was associated with a decrease in heat shock protein accumulation after cadmium exposure, but this negative correlation was not statistically significant. A positive correlation between Hsp70 accumulation and plasma cortisol concentration was observed after chromium and nickel exposures. The induction of cortisol as a stress response may be metal-specific. No statistically significant relationship between cortisol and Hsp70 synthesis was found. The quantification of three hepatic Hsp70 isoforms demonstrates the feasibility of applying heat shock response in O. mossambicus as a biomarker of exposure to pollutants in the aquatic environment.