Beta-adrenergic stimulation enhances the heat-shock response in fish.

We have taken advantage of the unique properties of nucleated rainbow trout (Oncorhynchus mykiss) red blood cells (rbcs) to demonstrate that beta-adrenergic stimulation with the agonist, isoproterenol, significantly enhanced the heat-induced induction of heat-shock proteins (Hsps) in trout rbcs without affecting hsp expression on its own. Furthermore, this beta-adrenergic potentiation of hsp expression occurred only at physiologically relevant concentrations of adrenergic stimulation. In further experiments, we found that adrenaline increased 100-fold and noradrenaline increased 50-fold in trout after a 1-h heat shock at 25 degrees C, approximately 12 degrees C above acclimation temperature.