Platelet aggregation and vasopressin receptors in patients with diabetes mellitus

Plasma vasopressin, vasopressin-induced platelet aggregation, and platelet vasopressin receptors were investigated in 10 normal subjects and 14 diabetic patients free of microangiopathy. Basal plasma vasopressin concentration was identical in two groups. Platelet aggregation induced by vasopressin as well as by epinephrine was not significantly altered in the diabetic patients. However, exploration of platelet V1-vasopressin receptors revealed in the diabetic group a dramatic reduction in the number of binding sites without alteration of the receptor affinity for tritiated vasopressin. Thus vasopressin-induced platelet aggregation in uncomplicated diabetes mellitus remains normal despite a decrease in the number of vasopressin receptors presumably due to alterations of the platelet membrane structure.