J Webber1, D Whitelaw, J M Smith, M Nattrass. 1. Diabetes Clinic, University Hospital Birmingham NHS Trust, Selly Oak Hospital, UK. m.desai@bham.ac.uk
Abstract
AIM: To assess whether resistance to the effects of insulin on lipid metabolism in type 2 diabetes mellitus parallels that demonstrated for glucose metabolism. 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 infusion technique were used in order to assess insulin effects on both glucose and lipid metabolism. RESULTS: Using the low-dose insulin infusion there were significant correlations between measures of insulin sensitivity for glucose metabolism and those for NEFA (r = 0.82, p < 0.01) and glycerol (r = 0.73, p < 0.01). Mean clamp glucose disposal was 33.4 micromol kgb.w.(-1) min(-1). There was no correlation between clamp glucose disposal and insulin sensitivity derived from the low-dose insulin infusion. CONCLUSIONS: At low insulin concentrations, insulin's effects on glucose metabolism (mainly suppression of hepatic glucose output) mirror those on inhibition of lipolysis. At the high insulin concentrations seen during the clamp, stimulation of glucose uptake provides a measure of maximal insulin action which does not parallel its physiological effects shown at lower concentrations.
AIM: To assess whether resistance to the effects of insulin on lipid metabolism in type 2 diabetes mellitus parallels that demonstrated for glucose metabolism. 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 infusion technique were used in order to assess insulin effects on both glucose and lipid metabolism. RESULTS: Using the low-dose insulin infusion there were significant correlations between measures of insulin sensitivity for glucose metabolism and those for NEFA (r = 0.82, p < 0.01) and glycerol (r = 0.73, p < 0.01). Mean clamp glucose disposal was 33.4 micromol kgb.w.(-1) min(-1). There was no correlation between clamp glucose disposal and insulin sensitivity derived from the low-dose insulin infusion. CONCLUSIONS: At low insulin concentrations, insulin's effects on glucose metabolism (mainly suppression of hepatic glucose output) mirror those on inhibition of lipolysis. At the high insulin concentrations seen during the clamp, stimulation of glucose uptake provides a measure of maximal insulin action which does not parallel its physiological effects shown at lower concentrations.