Heat Shock Proteins and Physiological Stress in Fish

Abstract

This paper reviews the generalized stress response in fish at the cellular and neuroendocrine levels. The focus of this review is to examine the possible relationships between the stress responses at these two levels in fish. It focuses primarily on the heat shock protein 70 (hsp70). Thus, the descriptions of the endocrine and the cellular stress responses are followed by a discussion of how hsps may be related to the stress hormones adrenaline and cortisol. Preliminary evidence shows that adrenaline causes an increase in hsp70 in primary cultures of rainbow trout hepatocytes. Cortisol does not directly affect hsp70 levels in fish tissues; however, in primary cultures of trout hepatocytes, cortisol decreased the stressor-induced increase in hsp 70. A wide range of abiotic and biological stressors have been shown to induce hsp induction in many types of fish cells, including cell lines, primary cell cultures, and in tissues from whole animals. Heat shock proteins has been implicated in the protection of sulphate transport in the renal epithelium of the flounder against the damaging effects of heat stress. Heat shock proteins likely confer thermotolerance in fish, as well as tolerance to cytotoxic effects of environmental contaminants and other non-thermal stressors.