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 an d SP30 levels together with plasma cortisol, glucose and ion concentrations , in response to handling stress (45 s holding in a net), intraperitoneal c ortisol implants, and heat shock (+10 degreesC). Handling and cortisol impl ants resulted in increased plasma cortisol and glucose levels. Heat shock f ollowing handling reduced plasma [Na+] below that observed in response to t he handling stress alone, and heat shock following cortisol implant signifi cantly 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 h eat shock suppressed the increase of SP70 levels in the gills. However, inc reased plasma cortisol concentrations alone did not attenuate gill tissue S P70 increase caused by heat shock. Physiological (10(-7) M) and pharmacolog ical (10(-5) M) concentrations of adrenaline caused increased levels of SP7 0 in hepatocytes. Addition of the beta -blocker propanolol blocked this res ponse to adrenaline. The results indicate that handling procedures do not r esult in an increase of hsp30 or hsp70 and may suppress hsp synthesis under certain circumstances.