Euglycemic hyperinsulinemic clamp to assess posthepatic glucose appearanceafter carbohydrate loading. 2. Evaluation of corn and mung bean starches in healthy men

Background: The rate of absorption of glucose from carbohydrates is importa nt in several aspects of health. We recently validated a noninvasive techni que in pigs, euglycemic hyperinsulinemic clamp plus oral carbohydrate loadi ng (OC-Clamp), to quantify the rate of net posthepatic appearance of glucos e after ingestion of carbohydrates. Objective: The OC-Clamp procedure was performed in 8 healthy men to compare the net posthepatic appearance of glucose after ingestion of 1 of 3 carboh ydrates. Design: Human volunteers underwent the OC-Clamp procedure at an insulin inf usion rate of 1.5 mU.kg(-1).min(-1) (n = 5). The oral carbohydrate load (1 g/kg) consisted of glucose, cornstarch, or mung bean starch. During the OC- Clamp procedure, the glucose infusion rate decreased during absorption to m aintain plasma gluco:se steady state and the decrease reflected the net pos thepatic appearance of glucose. In addition, carbohydrates were loaded with out insulin infusion (n = 6) and glycemic indexes were calculated (with glu cose as the reference), Results: The mean (+/-SEM) glycemic index of cornstarch was higher (95 +/- 18) than that of mung bean starch (51 +/- 13). In the OC-Clamp experiments, the posthepatic appearance of glucose and cornstarch did not differ signif icantly and represented 79.4 +/- 5.0% and 72.6 +/- 4.0%, respectively, of t he load after complete absorption (within 3 h). In contrast, the net posthe patic appearance of glucose from mung bean starch was significantly lower ( 35.6 +/- 4.6% of the load, P < 0.001) than that from glucose and cornstarch , even 4.5 h postprandially. Conclusions: The OC-Clamp technique allows a continuous assessment of net p osthepatic appearance of glucose after ingestion of carbohydrates and signi ficant discrimination between corn and mung bean starches.