Talanian Jason L, Tunstall Rebecca J, Watt Matthew J, Duong Mylinh, Perry Christopher G R, Steinberg Gregory R, Kemp Bruce E, Heigenhauser George J F, Spriet Lawrence L
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Am J Physiol Regul Integr Comp Physiol. 2006 Oct;291(4):R1094-9. doi: 10.1152/ajpregu.00130.2006. Epub 2006 May 11.
Skeletal muscle hormone-sensitive lipase (HSL) activity is increased by contractions and increases in blood epinephrine (EPI) concentrations and cyclic AMP activation of the adrenergic pathway during prolonged exercise. To determine the importance of hormonal stimulation of HSL activity during the onset of moderate- and high-intensity exercise, nine men [age 24.3 +/- 1.2 yr, 80.8 +/- 5.0 kg, peak oxygen consumption (VO2 peak) 43.9 +/- 3.6 ml x kg(-1) x min(-1)] cycled for 1 min at approximately 65% VO2 peak, rested for 60 min, and cycled at approximately 90% VO2 peak for 1 min. Skeletal muscle biopsies were taken pre- and postexercise, and arterial blood was sampled throughout exercise. Arterial EPI increased (P < 0.05) postexercise at 65% (0.45 +/- 0.10 to 0.78 +/- 0.27 nM) and 90% VO2 peak (0.57 +/- 0.34 to 1.09 +/- 0.50 nM). HSL activity increased (P < 0.05) following 1 min of exercise at 65% VO2 peak [1.05 +/- 0.39 to 1.78 +/- 0.54 mmol x min(-1) x kg dry muscle (dm)(-1)] and 90% VO2 peak (1.07 +/- 0.24 to 1.91 +/- 0.62 mmol x min(-1) x kg dm(-1)). Cyclic AMP content also increased (P < 0.05) at both exercise intensities (65%: 1.52 +/- 0.67 to 2.75 +/- 1.12, 90%: 1.85 +/- 0.65 to 2.64 +/- 0.93 micromol/kg dm). HSL Ser660 phosphorylation (approximately 55% increase) and ERK1/2 phosphorylation ( approximately 33% increase) were augmented following exercise at both intensities, whereas HSL Ser563 and Ser565 phosphorylation were not different from rest. The results indicate that increases in arterial EPI concentration during the onset of moderate- and high-intensity exercise increase cyclic AMP content, which results in the phosphorylation of HSL Ser660. This adrenergic stimulation contributes to the increase in HSL activity that occurs in human skeletal muscle in the first minute of exercise at 65% and 90% VO2 peak.
在长时间运动过程中，骨骼肌激素敏感性脂肪酶（HSL）的活性会因收缩以及血液中肾上腺素（EPI）浓度的升高和肾上腺素能途径的环磷酸腺苷激活而增强。为了确定在中高强度运动开始时激素对HSL活性刺激的重要性，9名男性[年龄24.3±1.2岁，体重80.8±5.0千克，峰值耗氧量（VO2峰值）43.9±3.6毫升·千克-1·分钟-1]以约65%VO2峰值的强度骑行1分钟，休息60分钟，然后以约90%VO2峰值的强度骑行1分钟。在运动前后进行骨骼肌活检，并在整个运动过程中采集动脉血样。运动后动脉EPI升高（P<0.05），在65%VO2峰值时（从0.45±0.10纳摩尔升至0.78±0.27纳摩尔）和90%VO2峰值时（从0.57±0.34纳摩尔升至1.09±0.50纳摩尔）。在65%VO2峰值[从1.05±0.39升至1.78±0.54毫摩尔·分钟-1·千克干肌肉（dm）-1]和90%VO2峰值（从1.07±0.24升至1.91±0.62毫摩尔·分钟-1·千克dm-1）运动1分钟后，HSL活性升高（P<0.05）。在两种运动强度下，环磷酸腺苷含量也均升高（P<0.05）（65%：从1.52±0.67升至2.75±1.12，90%：从1.85±0.65升至2.64±0.93微摩尔/千克dm）。在两种强度运动后，HSL Ser660磷酸化（增加约55%）和ERK1/2磷酸化（增加约33%）均增强，而HSL Ser563和Ser565磷酸化与休息时无差异。结果表明，在中高强度运动开始时动脉EPI浓度的升高会增加环磷酸腺苷含量，这导致HSL Ser660磷酸化。这种肾上腺素能刺激有助于在65%和90%VO2峰值运动的第一分钟内人体骨骼肌中HSL活性的增加。
