YAMADA, K., MORI, K. and GOTO, Y. Platelet Aggregation and Plasma Levelsof Beta-Thromboglobulin in Diabetes Mellitus. Tohoku J. exp. Med., 1981, 135 (4), 423-429-In view of the tendency toward vascular complications in diabetesmellitus, we studied platelet aggregation and plasma beta-thromboglobulin (β-TG) levels in 35 healthy controls, 25 non-diabetic patients with ischemic heartdisease (IHD) and 85 diabetic patients. Blood platelets from diabetic patientsshowed no significant hyperaggregation induced by ADP, collagen or epinephrine, as compared with controls and non-diabetic patients with IHD, nor could bedemonstrated significant differences in platelet aggregation between diabetics withdiabetic microangiopathies and those without diabetic vascular complications.Significantly high levels of plasma β-TG were observed in diabetics in comparisonwith those in controls and non-diabetic patients with IHD. Patients withdiabetic microangiopathy had more significantly elevated β-TG levels thandiabetics without diabetic microangiopathies. Diabetics without diabeticmicroangiopathy had similar levels of β-TG to those of controls and non-diabeticpatients with IHD. High levels of plasma β-TG in diabetics with diabetic microangiopathyseem to indicate a platelet hyperfunction in vivo due to diabeticvascular complications, -platelet aggregation; diabetic microangiopathy; beta-thromboglobulin; diabetes mellitus; ischemic heart disease