Chronobiology of catecholamine excretion in normal and diabetic men

The adrenomedullary response to stimuli is often elevated in poorly controlled insulin dependent diabetic patients, and it is controversial whether the adrenomedullary hyperactivity induces the suppression of the circadian rhythm of catecholamines. We have studied the urinary excretion of catecholamines in 11 diabetic patients during 48 h in 4-h collections. Eleven age and weight matched normal subjects served as controls. A circadian rhythm was detected for adrenaline and noradrenaline excretion both in normal and diabetic subjects, with the highest value for both catecholamines in the early afternoon. The mean daily adrenaline levels were significantly higher in diabetic than in control subjects (p less than 0.05). The dopamine excretion was correlated with noradrenaline excretion in normal subjects but did not show a definite circadian rhythm. We conclude that the adrenomedullary hyperactivity does not affect the rhythmic fluctuations of adrenaline and noradrenaline. The dopamine excretion does not show circadian variations and this probably reflects the absence of a single controlling oscillator.