Exercise training reduces skeletal muscle membrane arachidonate in the obese (fa/fa) Zucker rat

Kerry J. Ayre, Stephen D. Phinney, Anna B. Tang, Judith S. Stern

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Compared with the lean (Fa/-) genotype, obese (fa/fa) Zucker rats have a relative deficiency of muscle phospholipid arachidonate, and skeletal muscle arachidonate in humans is positively correlated with insulin sensitivity. To assess the hypothesis that the positive effects of exercise training on insulin sensitivity are mediated by increased muscle arachidonate, we randomized 20 lean and 20 obese weanling male Zucker rats to sedentary or treadmill exercise groups. After 9 wk, fasting serum, three skeletal muscles (white gastrocnemius, soleus, and extensor digitorum longus), and heart were obtained. Fasting insulin was halved by exercise training in the obese rat. In white gastrocnemius and extensor digitorum longus (fast-twitch muscles), but not in soleus (a slow-twitch muscle) or heart, phospholipid arachidonate was lower in obese than in lean rats (P < 0.001). In all muscles, exercise in the obese rats reduced arachidonate (P < 0.03, by ANOVA contrast). We conclude that improved insulin sensitivity with exercise in the obese genotype is not mediated by increased muscle arachidonate and that reduced muscle arachidonate in obese Zucker rats is unique to fast-twitch muscles.

Original languageEnglish (US)
Pages (from-to)1898-1902
Number of pages5
JournalJournal of Applied Physiology
Issue number5
StatePublished - 1998


  • Fatty acids
  • Insulin
  • Phospholipid

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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