Glucose and fatty acid metabolism in type 2 diabetes mellitus: an assessment using low-dose insulin infusion and the hyperinsulinaemic euglycaemic clamp

Aim: To assess whether resistance to the effects of insulin on lipid metabo lism in type 2 diabetes mellitus parallels that demonstrated for glucose me tabolism. Methods: Thirteen patients with type 2 diabetes were studied (mean age 56.2 years, mean body mass index (b.m.i.) 28.7 kg m(-2)). The hyperinsulinaemic euglycaemic clamp (2 mU insulin kg(-1) min(-1)) and a low-dose insulin inf usion technique were used in order to assess insulin effects on both glucos e and lipid metabolism. Results: Using the low-dose insulin infusion there were significant correla tions between measures of insulin sensitivity for glucose metabolism and th ose for NEFA (r = 0.82, p < 0.01) and glycerol (r = 0.73, p < 0.01). Mean c lamp glucose disposal was 33.4 mu mol kg b.w.(-1) min(-1). There was no cor relation between clamp glucose disposal and insulin sensitivity derived fro m the low-dose insulin infusion. Conclusions: At low insulin concentrations, insulin's effects on glucose me tabolism (mainly suppression of hepatic glucose output) mirror those on inh ibition of lipolysis. At the high insulin concentrations seen during the cl amp, stimulation of glucose uptake provides a measure of maximal insulin ac tion which does not parallel its physiological effects shown at lower conce ntrations.