Abstract

Wistar rats were submitted to prolonged training on a treadmill during twelve weeks. The urinary catecholamine excretion was measured after an exercisetest,performed once a week. This excretion with regard to control rats in specially increased after the first exercise-test, and afterwards tends to decrease with the training progression. However, if the variations in the urinary epinephrine and norepinephrine excretion are similar, the adrenergic response remains always relatively higher than the noradrenergic one. On the other hand, the heart rate during exercise is relatively lower in trained rats, which show a resting bradycardia. The heart rate failing associated with a catecholamine (and particularly norepinephrine) decrease would allow to consider that a sympathetic response reduction were bound to physical training. Moreover and adrenal hypertrophy is found which is likely related to an increase in activation of adrenal cortex due to physical conditionning. An improvement of norepinephrine methylation in adrenal medulla could be originated by this activation, The consequence of which being an increase in epinephrine urinary excretion Verf.-Referat