Objective:To establish a hyperinsulinemic euglycemic clamp technique in conscious rat

and to explore the effect of anesthesia and acute infusion of lipid on insulin sensitivity of rats.Methods:Rats divided into two groups were catheterized in the right jugular vein and left carotid artery and underwent a hyperinsulinemic-euglycemic clamp with or without infusion of lipid (Intralipid) and in unconscious and conscious state.Results:Infusion of lipid resulted in a decrease of insulin sensitivity by 30%( P <0.001 vs.control).In unconscious rats

the insulin sensitivity was decreased by 58%( P <0.001 vs. conscious).There was an antagonistic effect between infusion of lipid and anesthesia on insulin sensitivity of rats ( P <0.001).Conclusion:The increase of plasma free fatty acids induces insulin resistance.It would be better to carry out the hyperinsulinemic-euglycemic clamp under conscious state in rats.