Duclos M, Corcuff J B, Pehourcq F, Tabarin A
Laboratoire Neurogenetique et Stress, INSERM U471, 33076 Bordeaux, France.
Eur J Endocrinol. 2001 Apr;144(4):363-8. doi: 10.1530/eje.0.1440363.
Muscular exercise induces hypothalamo-pituitary-adrenal (HPA) axis activation and when regularly repeated, as in endurance training, leads to HPA axis adaptation. To assess whether non-professional endurance-trained (ET) men with a substantial training load and no clinical or biological features of HPA axis overactivity can present subtle alterations of HPA axis sensitivity to glucocorticoid negative feedback, nine ET men were subjected to HPA axis testing using the dexamethasone-corticotrophin-releasing hormone (CRH) test.
Nine endurance-trained men and eight healthy age-matched sedentary men were studied. Morning plasma cortisol and 24 h urinary free cortisol (UFC) were determined and a low dose dexamethasone suppression test (LDDST) was performed followed by CRH stimulation (dexamethasone-CRH test).
After a day without physical exercise, at 0800 h, plasma ACTH and cortisol concentrations, and the 24 h UFC and UFC/urinary creatinine (UC) ratio were similar in ET and sedentary men. By contrast, clear differences between the groups were seen in cortisol and ACTH responses to the dexamethasone-CRH test. In eight ET subjects, after LDDST, basal ACTH and cortisol levels were similar to those of sedentary men, whereas one ET subject displayed a poor suppression of cortisol level (131 nmol/l). After injection of CRH, however, three of nine ET men's cortisol levels were not suppressed by dexamethasone but instead displayed significant CRH-induced increase (peak cortisol: 88, 125 and 362 nmol/l). No sedentary subject exhibited any increase in cortisol levels.
Three of nine ET men with a mean maximum rate of O2 uptake (VO2, max) of 61 ml/kg per min, running 50-70 km per week, were resistant to glucocorticoid suppression during the combined dexamethasone-CRH test.
肌肉运动可诱导下丘脑 - 垂体 - 肾上腺（HPA）轴激活，当像耐力训练那样定期重复运动时，会导致HPA轴适应。为评估训练负荷较大且无HPA轴功能亢进临床或生物学特征的非专业耐力训练（ET）男性是否会出现HPA轴对糖皮质激素负反馈敏感性的细微改变，对9名ET男性进行了地塞米松 - 促肾上腺皮质激素释放激素（CRH）试验以检测HPA轴。
研究了9名耐力训练男性和8名年龄匹配的健康久坐男性。测定了早晨血浆皮质醇和24小时尿游离皮质醇（UFC），并进行了低剂量地塞米松抑制试验（LDDST），随后进行CRH刺激（地塞米松 - CRH试验）。
在一天无体育锻炼后，08:00时，ET男性和久坐男性的血浆促肾上腺皮质激素（ACTH）和皮质醇浓度、24小时UFC以及UFC/尿肌酐（UC）比值相似。相比之下，两组在皮质醇和ACTH对地塞米松 - CRH试验的反应上存在明显差异。在8名ET受试者中，LDDST后，基础ACTH和皮质醇水平与久坐男性相似，而1名ET受试者的皮质醇水平抑制不佳（131 nmol/l）。然而，注射CRH后，9名ET男性中有3人的皮质醇水平未被地塞米松抑制，反而显示出CRH诱导的显著升高（皮质醇峰值：88、125和362 nmol/l）。没有久坐受试者的皮质醇水平出现任何升高。
9名平均最大摄氧量（VO2，max）为每分钟61 ml/kg、每周跑步50 - 70公里的ET男性中有3人在联合地塞米松 - CRH试验期间对糖皮质激素抑制有抵抗性。
