OBJECTIVE To investigate the response of serum ghrelin and PYY to oral glucose and steamed-bread load and their relationships to insulin and glucose in nonobese and obese patients with type 2 diabetes. METHODS Ten obese subjects (Male: waist > or =90 cm, Female: waist > or =80 cm) and eleven nonobese subjects with type 2 diabetes were given oral glucose load and steamed-bread challenge in 2 consecutive days after blood glucose was controlled. The serum levels of ghrelin, PYY, insulin and glucose were measured with routine methods. RESULTS (1) Either in oral glucose or steamed-bread load tests, both fasting serum PYY and ghrelin levels of obese subjects were significantly lower than those of nonobese subjects. After taking glucose or steamed-bread, all subjects were observed the increase of PYY and ghrelin levels, which reached the peak at 30 min and 60 min respectively. However, there were no significant difference found between nonobese and obese group at 30 min, 60 min and 120 min (P=NS). (2) In all subjects, fasting serum PYY, ghrelin concentrations were inversely associated with waist circumferences and BMI but not WHR. (3) No correlations were observed between serum PYY and insulin, glucose at any time points. The ghrelin and insulin levels showed a correlation at 0 min (r = -0.591, P = 0.005), however, no correlations were found at any other time points. When comparing PYY, ghrelin AUC with the AUC of insulin and glucose, no correlations were found. (4) Ghrelin level was positively correlated with QUICKI, however, no correlation between PYY concentrations and QUICKI was noted. CONCLUSIONS In the subjects with type 2 diabetes, both PYY and ghrelin respond differently to glucose and bread, athough the calories are similar. PYY and ghrelin levels are inversely related to waist and BMI but not WHR. It is fasting ghrelin not PYY negatively associated with fasting insulin and positively with QUICKI.