GLUT 4 and insulin receptor binding and kinase activity in trained human muscle

J Physiol. 1993 Sep;469:615-24. doi: 10.1113/jphysiol.1993.sp019833.

Abstract

1. Physical training enhances sensitivity and responsiveness of insulin-mediated glucose uptake in human muscle. This study examines if this effect of physical training is due to increased insulin receptor function or increased total concentration of insulin-recruitable glucose transporter protein (GLUT 4). 2. Seven healthy young subjects carried out single leg bicycle training for 10 weeks at 70% of one leg maximal oxygen uptake (VO2,max). Subsequently biopsies were taken from the vastus lateralis muscle of both legs. 3. Single leg VO2,max increased for the trained leg (46 +/- 3 to 52 +/- 2 ml min-1 kg-1 (means +/- S.E.M., P < 0.05), and cytochrome c oxidase activity was higher in this compared to the untrained leg (2.0 +/- 0.1 vs. 1.4 +/- 0.1 nmol s-1 (mg muscle)-1, P < 0.05). Insulin binding as well as basal- and insulin-stimulated receptor kinase activity did not differ between trained and untrained muscle. The concentration of GLUT 4 protein was higher in the former (14.9 +/- 1.9 vs. 11.6 +/- 1.0 arbitrary units (micrograms protein)-1 in crude membranes, P < 0.05). The training-induced increase in GLUT 4 (26 +/- 11%) matched a previously reported increase in maximum insulin-stimulated leg glucose uptake (25 +/- 7%) in the same subjects, and individual values of the two variables correlated (correlation coefficient (r) = 0.84, P < 0.05). 4. In conclusion, in human muscle training induces a local contraction-dependent increase in GLUT 4 protein, which enhances the effect of insulin on glucose uptake. On the other hand, insulin receptor function in muscle is unlikely to be affected by training.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bicycling
  • Electron Transport Complex IV / metabolism
  • Glucose / metabolism
  • Glucose Transporter Type 4
  • Humans
  • Insulin / metabolism
  • Male
  • Monosaccharide Transport Proteins / metabolism*
  • Muscle Proteins*
  • Muscles / enzymology
  • Muscles / metabolism*
  • Oxygen Consumption / physiology
  • Physical Education and Training*
  • Receptor, Insulin / metabolism*
  • Regional Blood Flow / physiology

Substances

  • Glucose Transporter Type 4
  • Insulin
  • Monosaccharide Transport Proteins
  • Muscle Proteins
  • SLC2A4 protein, human
  • Electron Transport Complex IV
  • Receptor, Insulin
  • Glucose