HYPERTENSION AND ABNORMALITIES OF CARBOHYDRATE-METABOLISM POSSIBLE ROLE OF THE SYMPATHETIC NERVOUS-SYSTEM

To investigate the relationships between the sympathetic nervous syste m (SNS) and parameters of glucose metabolism in arterial hypertension, daily urinary excretion of catecholamines and plasma glucose, insulin , and C-peptide response to an oral glucose load (OGL) have been evalu ated in 77 untreated patients with mild-to-moderate essential hyperten sion and in 31 normotensive controls. Urinary excretion of norepinephr ine (UNE) was positively correlated with body mass index and with plas ma glucose levels both at fast and after OGL. No correlations were fou nd between urinary excretion of catecholamines and plasma insulin and C-peptide levels both at fast and in response to OGL. Because the freq uency distribution of UNE was bimodal, hypertensive subjects were sepa rated into two subgroups using an arbitrary cutoff, and the parameters of glucose metabolism were compared. Subjects with UNE > 205 mu g/day had greater levels of fasting glucose and greater glycemic response t o OGL than subjects with UNE < 205 mu g/day, whereas no significant di fferences between the groups were found in fasting and stimulated plas ma insulin and C-peptide. Thus, activation of SNS is related to glucos e tolerance but not hyperinsulinemia and insulin hypersecretion in ess ential hypertension. Plasma glucose levels, independent of insulin, ma y contribute to the relationship between SNS activity and blood pressu re in essential hypertension. (C) 1997 American Journal of Hypertensio n, Ltd.