Stress hormones and the cellular stress response in salmonids

The relationship between stress protein (SP) levels and the hormonal stress response in salmonids was examined through the measurement of gill SP70 and SP30 levels together with plasma cortisol, glucose and ion concentrations, in response to handling stress (45 s holding in a net), intraperitoneal cortisol implants, and heat shock (+10 degreesC). Handling and cortisol implants resulted in increased plasma cortisol and glucose levels. Heat shock following handling reduced plasma [Na+] below that observed in response to the handling stress alone, and heat shock following cortisol implant significantly lowered both plasma [Cl-] and [Na+] below that of fish receiving the cortisol implant alone. Increased SP70 levels occurred 1 h following the 2 h +10 degreesC heat shock. Handling the fish prior to the application of heat shock suppressed the increase of SP70 levels in the gills. However, increased plasma cortisol concentrations alone did not attenuate gill tissue SP70 increase caused by heat shock. Physiological (10(-7) M) and pharmacological (10(-5) M) concentrations of adrenaline caused increased levels of SP70 in hepatocytes. Addition of the beta -blocker propanolol blocked this response to adrenaline. The results indicate that handling procedures do not result in an increase of hsp30 or hsp70 and may suppress hsp synthesis under certain circumstances.