Plasma glucose, insulin, and lipoprotein concentrations were determined in 20 men with hypertension, and compared with values in 20 normotensive men of comparable age and body mass index. The results demonstrated a significant increase in both the plasma glucose and insulin response to a 75-g oral glucose challenge (two-way analysis of variance). In addition, a significant correlation existed between the plasma blood pressure. Finally, the greater the plasma glucose insulin response to oral glucose and both systolic and diastolic and insulin responses to oral glucose, the lower the plasma high-density lipoprotein concentrations, and the higher the ratio of plasma low-density lipoprotein cholesterol to high-density lipoprotein cholesterol. Thus, abnormalities of plasma glucose, insulin, and lipoprotein metabolism exist in patients with untreated hypertension, and these changes may contribute to the increased risk for coronary artery disease associated with hypertension.