1. During ninety-minute norepinephrine infusions, blood free fatty acid and ketone responses of Japanese nondiabetic and diabetic subjects were determined. Nonobese diabetic subjects with and without fasting hyperglycemia demonstrated significantly greater blood ketone elevations than nondiabetics.
2. An inverse correlation between obesity and blood ketone response to norepinephrine was observed in diabetics. This correlation could not be attributed to varying degrees of fasting hyperglycemia or free fatty acid elevation.
3. Nonobese diabetics with mild fasting hyperglycemia (90 to 150 mg. per 100 ml.) exhibited an unexpected greater increase in blood ketones than nonobese diabetics with moderate fasting hyperglycemia (150 to 250 mg. per 100 ml.). Differences in free fatty acid elevations were not responsible for this apparent paradox.
4. The magnitude of the hyperketonemic response, though dependent on free fatty acid elevation, seemed more sensitive to the degree of obesity and the fasting blood glucose level. Fractional ketone body measurements indicated that the blood ketone elevations were predominantly due to fihydroxybutyric acid increases.