期刊
JOURNAL OF APPLIED PHYSIOLOGY
卷 104, 期 4, 页码 931-937出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/japplphysiol.01151.2007
关键词
maximal activity; metabolic pathways; cycling
To examine the effects of repetitive bouts of heavy exercise on the maximal activities of enzymes representative of the major metabolic pathways and segments, 13 untrained volunteers [peak aerobic power ((V) over dotO(2 peak)) = 44.3 +/- 2.3 ml.kg(-1).min(-1)] cycled at similar to 91% (V) over dotO(2) peak for 6 min once per hour for 16 h. Maximal enzyme activities (V-max, mol.kg(-1).protein.h(-1)) were measured in homogenates from tissue extracted from the vastus lateralis before and after exercise at repetitions 1 (R1), 2 (R2), 9 (R9), and 16 (R16). For the mitochondrial enzymes, exercise resulted in reductions (P < 0.05) in cytochrome-c oxidase (COX, 14.6%), near significant reductions in malate dehydrogenase (4.06%; P = 0.06) and succinic dehydrogenase (4.82%; P = 0.09), near significant increases in beta-hydroxyacyl-CoA dehydrogenase (4.94%; P = 0.08), and no change in citrate synthase (CS, 2.88%; P = 0.37). For the cytosolic enzymes, exercise reduced (P < 0.05) Vmax in hexokinase (Hex, 4.4%), creatine phosphokinase (9.0%), total phosphorylase (13.5%), phosphofructokinase (16.6%), pyruvate kinase (PK, 14.1%) and lactate dehydrogenase (10.7%). Repetition-dependent reductions (P < 0.05) in Vmax were observed for CS (R1, R2 > R16), COX (R1, R2 > R16), Hex (1R, 2R > R16), and PK (R9 > R16). It is concluded that heavy exercise results in transient reductions in a wide range of enzymes involved in different metabolic functions and that in the case of selected enzymes, multiple repetitions of the exercise reduce average Vmax.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据