Müller M J, Dettmer A, Tettenborn M, Radoch E, Fichter J, Wagner T O, Balks H J, von zur Mühlen A, Selberg O
Abteilung Gastroenterologie und Hepatologie, Medizinische Hochschule, Hannover, Germany.
Eur J Appl Physiol Occup Physiol. 1996;74(3):246-57. doi: 10.1007/BF00377447.
The liver is central to the metabolic response to exercise but measurements of effects of reduced liver function on the physiological adaptation to exercise are scarce. We investigated metabolic, endocrine, pulmonary and haemodynamic responses to exercise in 15 healthy untrained controls (Co) and in 30 subjects with reduced liver function (i.e. liver cirrhosis, Ci). The following protocols were used: protocol 1 maximal oxygen uptake (VO2max) and anaerobic threshold (AT), protocol 2 stepwise increases in exercise intensity from 0 to 40% VO2max giving steady-stage conditions, protocol 3 1 h exercise at 20% VO2max. Muscle glycogen content was determined in 15 Ci. Spirometry was essentially normal in Ci.
protocol 1 Ci had impaired VO2max and reduced AT (P < 0.05). Basal plasma concentrations of insulin, glucagon, growth hormone and adrenaline were increased in Ci (P < 0.05); cortisol was normal. During exercise, only glucagon remained different between groups. In protocol 2 Ci had decreased resting respiratory exchange ratio (RQ: p < 0.05) associated with increased plasma concentrations of free fatty acids and glycerol. They had disproportionately enhanced lipolysis and RQ. heart rate (+24%), ventilation (+28%), thermal effects of exercise (+31%) and intrapulmonary shunt volume (+76%), which accounted for 11.7 (SD 3.0) or 7.4 (SD 0.9%) of cardiac output during exercise in Ci and Co, respectively (P < 0.05 for all the differences reported). The metabolic effects of Ci were independent of the clinical and nutritional state of the patients. In protocol 3 muscle glycogen content was highly variable in Ci, but mean values were normal [16.9 (SD 8.9) mumol.g-1 wet mass]. Glycogen content positively correlated with resting and exercise-induced RQ, but negatively correlated with the exercise-induced alterations in plasma glucose concentration. From these results we concluded that with reduced liver function VO2max and AT are reduced, but metabolic, pulmonary and haemodynamic responses per unit power output are enhanced. Muscle glycogen content would seem to contribute to the metabolic response, but its mobilization to be limited in individuals with reduced liver function.
肝脏是运动代谢反应的核心，但关于肝功能下降对运动生理适应影响的测量却很少。我们研究了15名健康未受过训练的对照组（Co）和30名肝功能下降受试者（即肝硬化，Ci）对运动的代谢、内分泌、肺和血流动力学反应。采用了以下方案：方案1最大摄氧量（VO2max）和无氧阈值（AT）；方案2运动强度从0逐步增加到VO2max的40%，达到稳定状态；方案3以VO2max的20%进行1小时运动。对15名Ci受试者测定了肌肉糖原含量。Ci受试者的肺活量测定基本正常。
方案1中，Ci受试者的VO2max受损，AT降低（P<0.05）。Ci受试者的基础血浆胰岛素、胰高血糖素、生长激素和肾上腺素浓度升高（P<0.05）；皮质醇正常。运动期间，两组之间只有胰高血糖素存在差异。在方案2中，Ci受试者静息呼吸交换率（RQ：p<0.05）降低，同时血浆游离脂肪酸和甘油浓度升高。他们的脂肪分解和RQ不成比例地增强。心率（+24%）、通气量（+28%）、运动热效应（+31%）和肺内分流容积（+76%），在Ci和Co受试者运动期间分别占心输出量的11.7（标准差3.0）或7.4（标准差0.9%）（所有报告差异P<0.05）。Ci受试者的代谢效应与患者的临床和营养状态无关。在方案3中，Ci受试者的肌肉糖原含量变化很大，但平均值正常[16.9（标准差8.9）μmol·g-1湿质量]。糖原含量与静息和运动诱导的RQ呈正相关，但与运动诱导的血浆葡萄糖浓度变化呈负相关。从这些结果我们得出结论，肝功能下降时VO2max和AT降低，但单位功率输出的代谢、肺和血流动力学反应增强。肌肉糖原含量似乎有助于代谢反应，但其动员在肝功能下降的个体中似乎受到限制。
