Fatty acid transport and FAT/CD36 are increased in red but not in white skeletal muscle of ZDF rats

Am J Physiol Endocrinol Metab. 2006 Sep;291(3):E675-82. doi: 10.1152/ajpendo.00096.2006. Epub 2006 May 9.

Abstract

An increased rate of fatty acid transport into skeletal muscle has been has been linked to the accumulation of intramuscular lipids and insulin resistance, and red muscles are more susceptible than white muscles in developing fatty acid-mediated insulin resistance. Therefore, we examined in Zucker diabetic fatty (ZDF) rats, relative to lean rats, 1) whether rates of fatty acid transport and transporters (FAT/CD36 and FABPpm) were upregulated in skeletal muscle during the transition from insulin resistance (week 6) to type 2 diabetes (weeks 12 and 24), 2) whether such changes occurred primarily in red skeletal muscle, and 3) whether changes in FAT/CD36 and GLUT4 were correlated. In red muscles of ZDF compared with lean rats, the rates of fatty acid transport were upregulated (+66%) early in life (week 6). Compared with the increase in fatty acid transport in lean red muscle from weeks 12-24 (+57%), the increase in fatty acid transport rate in ZDF red muscle was 50% greater during this same period. In contrast, no differences in fatty acid transport rates were observed in the white muscles of lean and ZDF rats at any time (weeks 6-24). In red muscle only, there was an inverse relationship between FAT/CD36 and GLUT4 protein expression as well as their plasmalemmal content. These studies have shown that, 1) before the onset of diabetes, as well as during diabetes, fatty acid transport and FAT/CD36 expression and plasmalemmal content are upregulated in ZDF rats, but importantly, 2) these changes occurred only in red, not white, muscles of ZDF rats.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Biological Transport / physiology*
  • Blood Glucose / metabolism
  • Blotting, Northern
  • Blotting, Western
  • CD36 Antigens / genetics
  • CD36 Antigens / metabolism*
  • Diabetes Mellitus, Type 2 / metabolism*
  • Fatty Acid-Binding Proteins / genetics
  • Fatty Acid-Binding Proteins / metabolism
  • Fatty Acids / blood
  • Fatty Acids / metabolism*
  • Gene Expression / genetics
  • Glucose Transporter Type 4 / metabolism
  • Insulin / blood
  • Male
  • Muscle Fibers, Fast-Twitch / metabolism*
  • Palmitic Acids / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Zucker
  • Sarcolemma / metabolism

Substances

  • Blood Glucose
  • CD36 Antigens
  • Fatty Acid-Binding Proteins
  • Fatty Acids
  • Glucose Transporter Type 4
  • Insulin
  • Palmitic Acids
  • RNA, Messenger
  • Slc2a4 protein, rat