[Effect of prednisolone on 3H-catecholamine synthesis in the adrenals of physically fatigued rats].

The effect of prednisolone on the synthesis of 3H-catecholamines by the adrenals of control and rats swimming for 8 hours was studied in experiments in vitro with the use of 3H-thyroxine as precursor. It was shown that in swimming rats, the synthesis of 3H-noradrenaline and 3H-adrenaline is inhibited by 25%, while the synthesis of 3H-dopamine remains unchanged. Addition of prednisolone to the incubation medium does not affect the rate of 3H-catecholamine synthesis by the adrenals of intact rats. Addition of prednisolone to the adrenals of swimming rats leads to the stimulation of the synthesis of 3H-noradrenaline and 3H-adrenaline by 72%, while the synthesis of 3H-dopamine gets stimulated by 56% relative to the synthesis rate of 3H-catecholamines during swimming. In the latter case the rate of 3H-catecholamine synthesis significantly exceeds the control level.