Insulin-like growth factor I has a direct effect on glucose and protein metabolism, but no effect on lipid metabolism in type 1 diabetes

J Clin Endocrinol Metab. 2004 Jan;89(1):425-32. doi: 10.1210/jc.2003-031274.


There is evidence of a metabolic role for IGF-I in type 1 diabetes, but it is unclear whether IGF-I acts indirectly by reducing GH secretion or has direct effects. Using stable isotopes we have investigated, on three separate occasions, the effect of a pulse of recombinant human GH, a sc injection of recombinant human IGF-I, and a placebo on glucose, lipid, and protein metabolism in subjects with type 1 diabetes during a basal insulin infusion and a hyperinsulinemic euglycemic clamp. Endogenous GH secretion was suppressed with octreotide. IGF-I reduced the hepatic glucose production rate (Ra), increased peripheral glucose uptake, and reduced protein breakdown during the basal insulin infusion (P < 0.05, P < 0.005, and P < 0.05, respectively, vs. placebo) and the hyperinsulinemic euglycemic clamp (P < 0.05, P < 0.005, and P < 0.05, respectively, vs. placebo). IGF-I had no effect on glycerol Ra, an index of lipolysis. GH increased glucose and glycerol Ra during the basal insulin infusion (P < 0.005 vs. placebo study), but the effects were no different from placebo during the clamp. In conclusion, IGF-I had a direct effect on glucose and protein metabolism, which was maintained during the hyperinsulinemic euglycemic clamp. This suggests that IGF-I acts in concert with insulin and may have an important role in maintaining glucose homeostasis and protein metabolism in type 1 diabetes.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Diabetes Mellitus, Type 1 / blood*
  • Fatty Acids, Nonesterified / blood
  • Glucagon / blood
  • Glucose / metabolism*
  • Glucose Clamp Technique
  • Glycerol / blood
  • Homeostasis
  • Human Growth Hormone / blood
  • Human Growth Hormone / pharmacology
  • Humans
  • Insulin / administration & dosage
  • Insulin / blood
  • Insulin-Like Growth Factor I / analysis
  • Insulin-Like Growth Factor I / pharmacology*
  • Kinetics
  • Leucine / blood
  • Lipids / blood*
  • Lipolysis
  • Liver / metabolism
  • Metabolic Clearance Rate
  • Oxidation-Reduction
  • Placebos
  • Proteins / metabolism*
  • Recombinant Proteins / pharmacology


  • Blood Glucose
  • Fatty Acids, Nonesterified
  • Insulin
  • Lipids
  • Placebos
  • Proteins
  • Recombinant Proteins
  • Human Growth Hormone
  • Insulin-Like Growth Factor I
  • Glucagon
  • Leucine
  • Glucose
  • Glycerol