Plasma Endothelinlike Immunoreactivity Levels in IDDM Patients with Microalbuminuria

OBJECTIVE: To determine whether plasma endothelin, a potent vasoconstrictor and growth factor for vascular smooth muscle, is elevated in microalbuminuric insulin-dependent diabetes mellitus patients. RESEARCH DESIGN AND METHODS: Plasma endothelinlike immunoreactivity was measured by radioimmunoassay in 15 microalbuminuric diabetic patients, 12 normoalbuminuric diabetic patients, and 12 control subjects. RESULTS: The mean levels of plasma endothelinlike immunoreactivity were raised in the normoalbuminuric patients (8.4 pM range 4.8-12.7 pM; P less than 0.01) and the microalbuminuric patients (10.2 pM range 5.6-31.1 pM; P less than 0.001) compared with control subjects (6.1 pM range 4.5-7.6 pM). Plasma endothelinlike immunoreactivity was also higher in the microalbuminuric patients compared with the normoalbuminuric patients (P less than 0.05). CONCLUSIONS: The increase in plasma endothelinlike immunoreactivity further confirms endothelial dysfunction in diabetes and this increase in plasma endothelin may contribute to the vascular disease prevalent in diabetes.