Plasma catecholamines and glucose during moderate exercise in the trout: comparison with bursts of violent activity.

A sensitive radioenzymatic method was used to measure the plasma adrenaline and noradrenaline levels in Salmo gairdneri during and after long but moderate exercise (30 min, 2.2 body length s-1), and after brief but violent exercise (3 min chasing). No significant change occurred under the former experimental conditions whereas adrenaline increased significantly under the second. Plasma glucose increased only after violent exercise. These results suggest that plasma catecholamines do not participate in physiological regulations related to exercise when trout is swimming at velocities up to 2.2 body length s-1.