Interrenal metallothionein and cortisol secretion in relation to Cd, Cu, and Zn exposure in yellow perch, Perca flavescens, from Abitibi lakes

Abstract

The concentrations of Zn, Cu, and Cd in the interrenal tissue and liver of yellow perch, Perca flavescens, sampled in six lakes in the mining region of Abitibi (Quebec) revealed a gradient of contamination: reference lakes, intermediate-contaminated lakes, and highly contaminated lakes. Interrenal and hepatic metallothionein concentrations followed a similar gradient, and there was a strong relationship between metallothionein and total metal (Zn + Cu + Cd) content in the liver and Cu + Cd content in the interrenals. Following a standardized confinement stress test, plasma cortisol and glucose were significantly higher in fish from reference lakes compared with the two most contaminated lakes. No differences in plasma chloride were observed. The secretory response of the interrenal tissue to in vitro stimulation by adrenocorticotropic hormone and dibutyryl cyclic AMP was significantly lower in fish from a contaminated lake compared with fish from a reference lake. Condition factor was significantly lower in yellow perch from the most contaminated lakes. This study demonstrated that a chronic field exposure to base metals increases hepatic and interrenal tissue metallothionein concentrations and disrupts the physiological capacity of yellow perch to generate the normal hormonal stress response.