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This Article Full Text Full Text (PDF) All Versions of this Article: 285/4/E827    most recent 00222.2002v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Tucker, M. Z. Articles by Turcotte, L. P. Search for Related Content PubMed PubMed Citation Articles by Tucker, M. Z. Articles by Turcotte, L. P.

Aging is associated with elevated muscle triglyceride content and increased insulin-stimulated fatty acid uptake

Department of Kinesiology and USC Diabetes Research Center, University of Southern California, Los Angeles, California 90089

Submitted 21 May 2002 ; accepted in final form 28 May 2003

The purpose of the present study was to examine the utilization of fatty acids (FA) and muscle substrates by skeletal muscle in young, middle-aged, and old adult rats under hyperglycemic and hyperinsulinemic conditions. Male Fischer 344 x Brown Norway rats aged 5, 15, or 24 mo underwent hindlimb perfusion with a medium of 20 mM glucose, 1 mM palmitate, 1,000 µU/ml insulin, [1-¹⁴C]palmitate, and [3-³H]glucose. Glucose uptake and palmitate delivery were similar among age groups. Palmitate uptake and oxidation as well as muscle protein concentration of fatty acid translocase (FAT/CD36) and plasma membrane fatty acid-binding protein (FABP_PM) were significantly increased (P 0.05) in 24- vs. 5- and 15-mo-old animals. Compared with 5- and 15-mo-old animals, pre- and postperfusion muscle triglyceride (TG) levels were significantly (P < 0.05) elevated 72–145% in red and 112–129% in white muscles of 24-mo-old animals. Palmitate uptake was associated with total preperfusion TG concentration (r² = 0.27, P < 0.05) and total TG synthesis rate (r² = 0.68, P < 0.05). These results indicate that, under insulin-stimulated conditions, FA uptake is significantly increased in old animals, which is associated with increased rates of TG synthesis and may contribute to the accumulation of TG in muscle of old animals.

fatty acid oxidation; Fischer 344 x Brown Norway; glycogen; intramuscular triglycerides; insulin resistance; CD36; plasma membrane fatty acid-binding protein

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				M. Z. Tucker and L. P. Turcotte Brief Food Restriction in Old Animals Decreases Triglyceride Content and Insulin-Stimulated Triglyceride Synthesis J. Gerontol. A Biol. Sci. Med. Sci., February 1, 2005; 60(2): 157 - 164. [Abstract] [Full Text] [PDF]