Glucose utilization, serum insulin, human growth hormone, and free fatty acids were studied in 18 unipolar depressed patients and 14 normal controls, using the intravenous glucose tolerance test. Patients were kept drug-free for at least two weeks before testing, and physical activity and diet were carefully controlled. Previously described abnormalities in the balance between glucose and free fatty adds were not seen, but endogenous depression was associated with lowered glucose utilization rate with insulin resistance. Changes in kinetics of membrane transport in endogenous depression which could account for this finding are discussed.