Dopamine-sodium relationship in type 2 diabetic patients

Diabetes mellitus is known to be associated with sodium retention. The aim of the present paper was to investigate the possible role of the renal dopaminergic system in the disturbed sodium homeostasis of Type 2 diabetic patients. The urinary dopamine excretion, which represents the local kidney production, was lower in Type 2 diabetic patients as compared to controls and decreased in insulin treated patients as compared to patients treated without insulin. Urinary dopamine excretion correlated positively with sodium excretion in non-insulin treated patients and in controls, but not in insulin treated patients. In contrast to findings in healthy Volunteers, an intravenous sodium load failed to increase the dopamine excretion in Type 2 diabetic patients, despite similar increments in sodium excretion. A low-dose dopamine infusion caused significantly lower natriuretic responses in insulin treated Type 2 diabetic patients as compared to controls, but not in non-insulin treated patients. These findings suggest that Type 2 diabetic patients display a derangement of the renal dopaminergic system, which is accentuated by insulin treatment. Copyright (C) 1996 Elsevier Science Ireland Ltd.