Correlates of venous catecholamine concentrations in patients with type 1 diabetes during a cold pressor test.

In some patients with type 1 diabetes, various physiologic reactions during a cold pressor test (CPT) are impaired. Whether this is caused by diabetic autonomic neuropathy, disturbed secretion of catecholamines, or disturbed blood glucose control is unknown. The authors, therefore, performed CPTs in patients with type 1 diabetes and in control subjects. They measured blood glucose concentrations, insulin concentrations, cardiac autonomic reflexes, and (before and after the CPT) venous catecholamine concentrations and analyzed correlations between these variables. Twenty-two patients with type 1 diabetes (17 men, 5 women; mean age ± SD, 26.6±6.5 y; diabetes duration, 7.6±0.7 y; glycosylated hemoglobin concentration, 7.7±2.4%) and 35 control subjects with comparable age and gender distributions were studied. Venous catecholamines were measured before and at the end of a 5-minute CPT. In patients with diabetes, only noradrenaline concentrations increased during the CPT, whereas adrenaline concentrations that were already increased at rest did not change. Adrenaline concentrations correlated inversely with insulin concentrations. In control subjects, both adrenaline and noradrenaline increased significantly during the CPT. In both groups, the magnitude of the individual change in catecholamine concentrations was inversely correlated with the respective resting concentration. Changes in catecholamines, cardiovascular reflex tests, and blood glucose concentrations did not correlate with blood pressure changes. The authors conclude that, in patients with diabetes, resting adrenaline concentrations are related to insulin concentrations. Contrary to control subjects, in patients with diabetes, only noradrenaline increased during CPTs. In both groups, changes in catecholamine concentrations after the CPT were inversely related to the respective resting concentrations.