Effects of diet and exercise on muscle and liver intracellular lipid contents and insulin sensitivity in type 2 diabetic patients

J Clin Endocrinol Metab. 2005 Jun;90(6):3191-6. doi: 10.1210/jc.2004-1959. Epub 2005 Mar 15.

Abstract

Insulin resistance is associated with the circulating free fatty acid (FFA) level and intracellular lipid content in muscle and liver. We investigated the effect of 2-wk diet and exercise therapy on total adiposity, circulating FFA, intracellular lipid content in muscle and liver, and peripheral insulin sensitivity. Type 2 diabetic patients were divided into a diet group (n = 7) and a diet plus exercise group (n = 7). We performed a hyperinsulinemic-euglycemic clamp study before and after treatment. Intramyocellular lipid (IMCL) in the tibialis anterior muscle and intrahepatic lipid (IHL) were evaluated by (1)H-magnetic resonance spectroscopy. Fasting FFA were not altered, and total body fat showed a slight, but significant, decrease in both groups after treatment. IMCL was decreased by 19%, and the glucose infusion rate was increased by 57% in the diet plus exercise group, whereas neither IMCL nor glucose infusion rate was significantly altered in the diet group. However, IHL showed a significant decrease in both groups. In summary, we found that 2 wk of diet and exercise decreased IMCL and increased muscle insulin-mediated glucose uptake, whereas diet with or without exercise decreased IHL. These effects were evident despite a small decrease in body fat and were observed independently of fasting FFA levels.

MeSH terms

  • Blood Glucose / drug effects
  • Blood Glucose / metabolism
  • Body Mass Index
  • Diabetes Mellitus, Type 2 / metabolism
  • Diabetes Mellitus, Type 2 / physiopathology*
  • Diet, Diabetic*
  • Exercise / physiology*
  • Female
  • Glucose Clamp Technique
  • Glycated Hemoglobin A / metabolism
  • Humans
  • Hyperinsulinism / blood
  • Insulin / pharmacology
  • Insulin / supply & distribution
  • Lipid Metabolism*
  • Liver / metabolism*
  • Liver Function Tests
  • Male
  • Middle Aged
  • Muscle, Skeletal / metabolism*

Substances

  • Blood Glucose
  • Glycated Hemoglobin A
  • Insulin