Calorie restriction initiated at middle age improved glucose tolerance without affecting age-related impairments of insulin signaling in rat skeletal muscle

Seongjoon Park, Toshimitsu Komatsu, Hiroko Hayashi, Haruyoshi Yamaza, Takuya Chiba, Yoshikazu Higami, Kazunao Kuramoto, Isao Shimokawa

Research output: Contribution to journalArticle

17 Citations (Scopus)


Calorie restriction (CR) may affect glucose tolerance via modulation of the insulin action in skeletal muscle. The present study investigated the effect of CR initiated at middle age in rats bearing glucose intolerance, in comparison with CR at a younger age. Male F344 rats at 2.5 and 18 months (mo) of age were fed ad libitum (AL) or 30% CR diets for 4-4.5 mo, subjected to glucose tolerance testing, and then sacrificed 15 min after intraperitoneal glucose or saline injection to evaluate glucose-stimulated insulin response and subsequent activation of insulin signaling molecules. The protein abundance of phosphorylated (p) insulin receptors, p-Akt, and p-atypical PKC and the membrane fraction of glucose transporter 4 in quadriceps femoris muscle (QFM) were analyzed by EIA or immunoblotting. CR initiated either at young or middle age improved glucose tolerance with a lower serum insulin response to glucose. However, middle-aged CR did not improve aging-related impairments in insulin signaling in QFM. The present results emphasized the possibilities of CR activation of an insulin-independent mechanism in skeletal muscle and also of the involvement of non-muscle tissues in glucose uptake.

Original languageEnglish
Pages (from-to)837-845
Number of pages9
JournalExperimental Gerontology
Issue number9
Publication statusPublished - 2006 Sep
Externally publishedYes



  • Aging
  • Calorie restriction
  • Glucose intolerance
  • Insulin resistance
  • Insulin signal
  • Skeletal muscle

ASJC Scopus subject areas

  • Ageing
  • Medicine(all)

Cite this