High sucrose diet and exercise: Effects on insulin-receptor function of 12- and 24-mo-old Sprague-Dawley rats

K. C. Eiffert, R. B. McDonald, J. S. Stern

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The purpose of this study was to evaluate the effect of aging (12 vs. 24 mo) on skeletal muscle insulin receptor function of male Sprague-Dawley rats fed either a 33% sucrose (wt/wt) or sucrose-free diet. The effect of exercise in combination with the sucrose diet was also evaluated by exercising half of the sucrose-fed group on a motorized treadmill. Insulin-receptor function was assessed in vitro by measuring the binding capacity of [125I]-insulin to partially purified receptors of the biceps femoris and vastus lateralis. Tyrosine kinase activity was measured as an index of postreceptor function. Insulin-receptor number was significantly decreased in 24-mo-old sucrose-fed rats compared to 12-mo-old rats fed the sucrose or sucrose-free diets. The affinity of insulin for the receptor did not significantly differ among groups. Maximal tyrosine kinase activity in vastus lateralis was significantly decreased in 12-mo-old sucrose-fed rats compared with sedentary 24-mo-old rats fed the sucrose-free diet or 24-mo-old rats fed the sucrose diet in combination with exercise. Exercise prevented the decrease in receptor function in both 12- and 24-mo-old sucrose-fed rats as measured by insulin binding and tyrosine kinase activity. These data suggest that diet and/or exercise rather than aging per se has a greater influence on insulin-receptor function.

Original languageEnglish (US)
Pages (from-to)1081-1089
Number of pages9
JournalJournal of Nutrition
Volume121
Issue number7
StatePublished - 1991

Keywords

  • Aging
  • Insulin binding
  • Insulin resistance
  • Rats
  • Skeletal muscle

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

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