Exercise training does not compensate for age-related decrease in myocardial GLUT-4 content.

J L Hall; R S Mazzeo; D A Podolin; G D Cartee; W C Stanley

doi:10.1152/jappl.1994.76.1.328

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PubMed · 8175525

Exercise training does not compensate for age-related decrease in myocardial GLUT-4 content.

J L Hall·R S Mazzeo·D A Podolin·G D Cartee·W C Stanley

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Abstract

We assessed the effects of age and endurance exercise training (treadmill running at 75% maximal running capacity, 1 h/day, 5 days/wk for 10 wk) on the total concentration of insulin-regulatable glucose transporters (GLUT-4) and GLUT-4 mRNA levels in the myocardium of male Fischer 344 rats aged 7, 15, and 25 mo. Myocardial GLUT-4 concentration was quantified with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting and detected with a polyclonal antibody to the GLUT-4 transporter. Myocardial GLUT-4 mRNA levels were quantified with slot-blot analysis and a cDNA probe for GLUT-4. Myocardial GLUT-4 concentration in the 25-mo group decreased 27 and 20% compared with the 7- and 15-mo group, respectively (P < 0.0001 and P < 0.003). GLUT-4 mRNA also decreased significantly in the 25-mo group compared with the 7-mo group (20% in the trained and 11% in the untrained group, P < 0.05). Endurance training did not significantly affect myocardial GLUT-4 concentrations in any age group despite a significant increase in GLUT-4 mRNA in the 7- and 25-mo trained groups. In conclusion, myocardial GLUT-4 protein levels in the rat are significantly decreased with age but are unaffected by 10 wk of treadmill running.

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Aging Animals Blood Glucose Blotting, Western Body Weight Electrophoresis, Polyacrylamide Gel Glucose Transporter Type 4 Glycolysis Male Monosaccharide Transport Proteins Muscle Proteins Myocardium Organ Size Physical Conditioning, Animal RNA, Messenger Rats Rats, Inbred F344 Journal Article Research Support, U.S. Gov't, P.H.S.

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J L Hall, R S Mazzeo, D A Podolin, G D Cartee, W C Stanley. 1994. Exercise training does not compensate for age-related decrease in myocardial GLUT-4 content.. https://doi.org/10.1152/jappl.1994.76.1.328

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