Parallel insulin-like growth factor I and insulin resistance in muscles of rats fed a high fat diet.
The possibility of a similarity between insulin-like growth factor-I (IGF-I) and insulin resistance in epitrochlearis muscles of rats fed a high fat diet [20% (wt/wt) fat] vs. a low fat diet [5% (wt/wt) fat] was investigated. Half-maximally and maximally effective concentrations of IGF-I- and insulin-stimulated 3-O-methyl-glucose transport were 2.32 and 25 nM, respectively, for IGF-I, compared with 0.79 and 20 nM for insulin. The high fat diet reduced both responsiveness and sensitivity of IGF-I-stimulated 3-O-methyl-glucose transport in parallel with the impaired insulin-stimulated 3-O-methyl-glucose transport. IGF-I binding at 2.5 nM to incubated epitrochlearis muscle was also decreased by the high fat diet (P < 0.05). Thus, the high fat diet caused simultaneous IGF-I and insulin resistance in rat skeletal muscle. The IGF-I resistance induced by feeding the high fat diet seems at least partially due to a reduction in IGF-I binding.
Liu
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S
Department of Physical Education and Sport Studies, University of Alberta, Edmonton, Canada.
Baracos
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Quinney
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HA
Le Bricon
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T
Clandinin
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MT
D019325:3-O-Methylglucose; D000818:Animals; D001692:Biological Transport; D004041:Dietary Fats / Q000008:administration & dosage* / Q000494:pharmacology; D004351:Drug Resistance; D005260:Female; D007333:Insulin Resistance; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008757:Methylglucosides / Q000493:pharmacokinetics; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004041:Dietary Fats; D008757:Methylglucosides; D019325:3-O-Methylglucose; D007334:Insulin-Like Growth Factor I