Glycemic response using an oral load of fructose, glucose, and sucrose was measured in men and in premenopausal and postmenopausal women after being grouped by differences in erythrocyte superoxide dismutase activity (SOD). Blood was drawn at O, 1/2, 1, 2, and 3 hr postload. Indices of copper status, carbohydrate tolerance, lactate, and uric acid levels were determined. Premenopausal women had lower plasma lactate, glucose, and fructose levels at I/2 hour after the carbohydrate loads compared to postmenopausal women and men. Men had higher plasma uric acid responses to the carbohydrate loads than women. The fructose load produced higher plasma lactate and uric acid levels compared to sucrose and glucose. Postmenopausal women had higher plasma lipids, ceruloplasmin, and plasma copper levels than premenopausal women and men. SOD was used to divide the three subject groups into those with low (<269 U/ml) and normal (494-598 U/ml) activity. Fasting plasma triglyceride and the insulin and uric acid responses after the carbohydrate loads were significantly higher in the normal SOD group compared to the low SOD group. SOD activity did not correlate with other parameters of copper nutriture such as ceruloplasmin and plasma copper or with dietar3" copper intake.