Increased insulin sensitivity is associated with reduced insulin and glucagon secretion and increased insulin clearance in man

J Clin Endocrinol Metab. 2003 Mar;88(3):1264-70. doi: 10.1210/jc.2002-021547.

Abstract

Insulin secretion is increased in insulin resistance. In this study, we examined whether high insulin sensitivity results in low insulin secretion. Twelve male master athletes [age 25.6 +/- 4.1 (mean +/- SD) yr] and seven male sedentary students (age 25.0 +/- 2.0 yr) underwent a hyperinsulinemic, euglycemic clamp and a glucose-dependent arginine stimulation test. Athletes had high insulin sensitivity [230 +/- 18 vs. 92 +/- 12 (nmol glucose/kg.min)/(pmol insulin/liter), P < 0.001] and low insulin response to arginine (at fasting glucose 135 +/- 22 vs. 394 +/- 60 pmol/liter, P < 0.001), which resulted in unaltered disposition index (32.8 +/- 3.8 vs. 33.5 +/- 3.3 micro mol glucose/kg.min, NS). Also, the C-peptide response to arginine was reduced (at fasting glucose 0.71 +/- 0.09 vs. 0.89 +/- 0.09 nmol/liter, P = 0.034). However, the C-peptide reduction was not as large as the insulin reduction yielding increased disposition index in athletes when calculated from C-peptide data (184 +/- 9 vs. 76 +/- 11 micro mol glucose/kg.min, P < 0.001). This difference is explained by increased insulin clearance among the athletes during the first 5 min after arginine (81.1% +/- 1.8% vs. 53.6% +/- 4.7%, P < 0.001). Also, the glucagon response to arginine was reduced in the athletes (58.8 +/- 6.7 vs. 90.1 +/- 9.9 ng/liter at fasting glucose, P = 0.009). We conclude that high insulin sensitivity results in low islet hormone secretion and increased insulin clearance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • C-Peptide / analysis
  • Fatty Acids, Nonesterified / blood
  • Glucagon / metabolism*
  • Humans
  • Insulin / metabolism
  • Insulin / pharmacology*
  • Islets of Langerhans / metabolism*
  • Male
  • Metabolic Clearance Rate

Substances

  • C-Peptide
  • Fatty Acids, Nonesterified
  • Insulin
  • Glucagon