BACKGROUND: Excessive secretion of glucagon contributes to metabolic disturbance in type 2 diabetes. A hyperglucagonemic state is likely to be involved in increased hepatic glucose output resulting from both gluconeogenesis and glycogenolysis. The mechanism of hyperglucagonemia, though still unclear, is explained, in part, by the decreased sensitivity of cells to insulin or glucose and disturbances of the normal oscillatory secretory pattern of insulin. The aim of the study was to determine the extent of glucagon excess and its related factors in Korean patients with type 2 diabetes. METHODS: The subjects of this study were 21 controls and 102 type 2 diabetic patients. The blood glucose, glucagon and insulin concentrations were measured at 0, 30, 60, 90 and 120 min after ingestion of 75 g of glucose, and the areas under the curve (AUC) calculated. RESULTS: The AUC of plasma glucose (AUCgc) was significantly higher in the type 2 diabetic patients than in the controls (2,026.1585.8 vs. 854.8190.3 mmol/min, P<0.01), but there was no difference in the AUC of plasma glucagon (AUCgn) between the two groups. The AUCgn in the type 2 diabetic patients was positively correlated with the duration of diabetes (r=0.202, P<0.05) or HbA1c (r=0.208, P<0.05). The AUC of serum insulin (AUCin) was negatively correlated with the duration of diabetes (r=-0.291, P<001). AUCgn, AUCgc and HbA1c in long-term diabetic patients (duration of diabetes 10 years, n=32) were significantly higher compared with recently diagnosed patients (duration of diabetes <1 year, n=38) (11,362.35,981.9 vs. 9,097. 22,990.4 ng/min; 2,119.9519.0 vs. 1,832.2477.6 mmol/min; 9.52.0 vs. 8.32.1%, P<0.05). In addition, the AUCin and insulinogenic index in long-term patients were significantly lower compared with recently diagnosed patients. (Eds note: the highlighted figures are confusing, due to your various uses of commas and period marks, olease clarify?) CONCLUSIONS: Our results suggest that duration of diabetes and poor glycemic control might be closely associated with relative hyperglucagonemia in Korean type 2 diabetic paticnts.