Normal insulin sensitivity and IMCL content in overweight humans are associated with higher fasting lipid oxidation

Gianluca Perseghin, Paola Scifo, Massimo Danna, Alberto Battezzati, Stefano Benedini, Elena Meneghini, Alessandro Del Maschio, Livio Luzi

Research output: Contribution to journalArticle

Abstract

Intramyocellular lipid (IMCL) storage is considered a local marker of whole body insulin resistance; because increments of body weight are supposed to impair insulin sensitivity, this study was designed to assess IMCL content, lipid oxidation, and insulin action in individuals with a moderate increment of body fat mass and no family history of diabetes. We studied 14 young, nonobese women with body fat 30% (n = 7) and 14 young, nonobese men with body fat 25% (n = 7) by means of the euglycemic-insulin clamp to assess whole body glucose metabolism, with indirect calorimetry to assess lipid oxidation, by localized 1H NMR spectroscopy of the calf muscles to assess IMCL content, and with dual-energy X-ray absorptiometry to assess body composition. Subjects with higher body fat had normal insulin-stimulated glucose disposal (P = 0.80), IMCL content in both soleus (P = 0.22) and tibialis anterior (P = 0.75) muscles, and plasma free fatty acid levels (P = 0.075) compared with leaner subjects in association with increased lipid oxidation (P <0.05), resting energy expenditure (P = 0.046), resting oxygen consumption (P = 0.049), and plasma leptin levels (P <0.01) in the postabsorptive condition. In conclusion, in overweight subjects, preservation of insulin sensitivity was combined with increased lipid oxidation and maintenance of normal IMCL content, suggesting that abnormalities of these factors may mutually determine the development of insulin resistance associated with weight gain.

Original languageEnglish
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume283
Issue number3 46-3
Publication statusPublished - Sep 1 2002

Keywords

  • Insulin resistance
  • Intramyocellular lipid content
  • Leptin
  • Lipid oxidation
  • Nuclear magnetic resonance spectroscopy
  • Tumor necrosis factor-α

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry

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