Effect of postexercise carbohydrate supplementation on glucose uptake-associated gene expression in the human skeletal muscle.
We previously found that the exercise-induced elevation in GLUT4 mRNA of rat muscle can be rapidly down-regulated when glucose is given immediately following exercise. The purpose of this study was to determine the effect of postexercise carbohydrate diet on GLUT4 and hexokinase (HK) II mRNA levels in the human skeletal muscle. Eight untrained male subjects (age, 20.7+/-3.1 years) exercised for 60 min on a cycle ergometer at a 70-75% maximal oxygen consumption. The postexercise dietary treatment was performed in a crossover design. Immediately after the exercise, a diet with 70% carbohydrate content (1 g per kilogram of body weight; 356+/-19.8 kcal) was given to half of the subjects (eaten in 10 min) followed by a 3-h recovery, while the control subjects remained unfed for 3 h. Biopsies were performed on the deep portion of the vastus lateralis muscle of all subjects immediately after the exercise and 3 h after the carbohydrate ingestion. Blood glucose and serum insulin concentrations were measured every 30 min for 3 h. At the end of the 3-h recovery, blood glucose and serum insulin levels were not different from control levels, indicating that the oral carbohydrate was mostly disposed in the body within 3 h. In addition, GLUT4 and HK II mRNA levels were significantly lowered in the exercised human skeletal muscle in subjects receiving the carbohydrate diet. In conclusion, the present study demonstrates that GLUT4 mRNA and HK II mRNA in the exercised human skeletal muscle were significantly lowered by a high-carbohydrate diet.
Cheng
I-Shiung
IS
Department of Nutrition and Food Sciences, Fu-Jen Catholic University, Taipei, Taiwan 242, ROC.
Lee
Ning-Yuean
NY
Liu
Kai-Li
KL
Liao
Su-Fen
SF
Huang
Chiung-Hsueh
CH
Kuo
Chia-Hua
CH
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D015536:Down-Regulation; D015444:Exercise / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D006593:Hexokinase / Q000096:biosynthesis; D006801:Humans; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis*; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; D006593:Hexokinase; D005947:Glucose