Muscle enzyme activity in humans: role of substrate availability and training

• Published in: The American journal of physiology Vol. 272; no. 5; p. R1620
• Main Authors: Helge, J.W. (University of Copenhagen, Copenhagen, Denmark.), Kiens, B
• Format: Journal Article
• Language: English
• Published: United States 01.05.1997
• Subjects: 3-Hydroxyacyl CoA Dehydrogenases - metabolism; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Adult; Biopsy; Citrate (si)-Synthase - metabolism; Dietary Carbohydrates - metabolism; Dietary Fats - metabolism; Dietary Proteins - metabolism; Energy Intake; GENERO HUMANO; GENRE HUMAIN; Hexokinase - metabolism; Humans; INGESTION DE NUTRIENTES; INGESTION DE SUBSTANCES NUTRITIVES; Male; MUSCLE; Muscle, Skeletal - enzymology; MUSCULOS; Physical Fitness
• ISSN: 0002-9513; 2163-5773
• DOI: 10.1152/ajpregu.1997.272.5.r1620

To study the effect of nutrient intake (substrate flux) and training on muscle enzyme activities, 36 untrained healthy men adapted for 7 wk to a fat-rich or a carbohydrate-rich diet. Ten of the 18 subjects on each diet completed an endurance training program, and the remaining 8 served as controls. Maximal oxygen uptake was increased (11%) in the trained groups (P 0.05) Irrespective of training, beta-hydroxyacyl-CoA-dehydrogenase activity in the vastus lateralis muscle was significantly increased by an average of 25% after adaptation to a fat-rich diet and was unchanged after adaptation to a carbohydrate-rich diet. In contrast, irrespective of diet, muscle citrate synthase activity and hexokinase activity were increased (P 0.05) after adaptation to training by 17 and 18% in the group fed the carbohydrate-rich diet and by 17 and 12% in the group fed the fat-rich diet, respectively, and were unchanged in the two control groups. We suggest that diet can affect muscle enzymatic adaptation, presumably through an effect on the substrate flux