Duclos M, Corcuff J B, Arsac L, Moreau-Gaudry F, Rashedi M, Roger P, Tabarin A, Manier G
Laboratoire de Biologie Appliquée à L'Education Physique et aux Sports et Laboratoire Performance Sportive et Santé, Université de Bordeaux II, France.
Clin Endocrinol (Oxf). 1998 Apr;48(4):493-501. doi: 10.1046/j.1365-2265.1998.00334.x.
The present study was conducted in order to describe human hypothalamo-pituitary adrenal (HPA) axis adaptation in a model of repeated physical stress (endurance training) that causes a moderate increase in cortisol levels.
We performed the same stimulation tests (adrenal stimulation with ACTH or pituitary stimulation with combined CRH/LVP) in a population of 8 endurance-trained athletes in two distinct situations: resting (baseline cortisol values) and 2 h after the end of strenuous exercise (increased cortisol values) to evaluate the HPA axis sensitivity to endogenous sustained increases in cortisol concentrations.
During these tests, saliva and plasma cortisol (Fs and Fp, respectively) were assessed and compared.
Cortisol values in both plasma and saliva at the end of 2 h of exercise were significantly higher than in rested controls: Fs 11.5 +/- 1.3 vs 6.5 +/- 0.8 nmol.l-1 and Fp 428 +/- 36 vs 279 +/- 27 nmol.l-1 (post exercise vs post rest sessions, respectively, P < 0.001 for both). After either hormone test (CRH/LVP or ACTH), cortisol levels in plasma and saliva increased similarly when rest was compared to post exercise. Saliva variations (delta %) under exogenous hormone stimulation were dramatically greater than plasma variations. For example, under ACTH stimulation, the relative increments in cortisol were on control day: delta Fs 980 +/- 139 vs delta Fp 218 +/- 43% (saliva vs plasma, respectively, P < 0.05) and on exercise day: delta Fs 605 +/- 89 vs delta Fp 102 +/- 14% (saliva vs plasma, respectively, P < 0.05).
In endurance-trained athletes, displaying a moderate but sustained endogenous cortisol increase: (1) ACTH responses following pituitary stimulation are not blunted, (2) cortisol responses following maximal adrenal stimulation are not blunted. Our results favour the hypothesis of a decreased pituitary sensitivity to cortisol negative feedback whereas the hypothesis of a major decreased adrenal sensitivity to ACTH was discarded. The greater ability of saliva assays to detect a cortisol increase strongly supports its use in the study of HPA physiology, whether under basal or dynamic conditions.
本研究旨在描述在反复体力应激（耐力训练）模型中人类下丘脑 - 垂体 - 肾上腺（HPA）轴的适应性，该模型会使皮质醇水平适度升高。
我们在8名耐力训练运动员群体中，于两种不同情况下进行相同的刺激试验（用促肾上腺皮质激素刺激肾上腺或用促肾上腺皮质激素释放激素/赖氨酸加压素联合刺激垂体）：静息状态（基础皮质醇值）和剧烈运动结束后2小时（皮质醇值升高），以评估HPA轴对皮质醇浓度内源性持续升高的敏感性。
在这些试验期间，对唾液和血浆皮质醇（分别为Fs和Fp）进行评估并比较。
运动2小时结束时，血浆和唾液中的皮质醇值均显著高于静息对照组：Fs分别为11.5±1.3与6.5±0.8 nmol·l⁻¹，Fp分别为428±36与279±27 nmol·l⁻¹（分别为运动后与静息后时段，两者P均<0.001）。在任何一种激素试验（促肾上腺皮质激素释放激素/赖氨酸加压素或促肾上腺皮质激素）后，与运动后相比，静息时血浆和唾液中的皮质醇水平升高情况相似。外源性激素刺激下唾液的变化（δ%）显著大于血浆的变化。例如，在促肾上腺皮质激素刺激下，皮质醇的相对增量在对照日为：δFs 980±139与δFp 218±43%（分别为唾液与血浆，P<0.05），在运动日为：δFs 605±89与δFp 102±14%（分别为唾液与血浆，P<0.05）。
在耐力训练的运动员中，表现出适度但持续的内源性皮质醇升高：（1）垂体刺激后的促肾上腺皮质激素反应未减弱，（2）最大肾上腺刺激后的皮质醇反应未减弱。我们的结果支持垂体对皮质醇负反馈敏感性降低的假说，而肾上腺对促肾上腺皮质激素敏感性大幅降低的假说被摒弃。唾液检测在检测皮质醇升高方面更强的能力有力地支持了其在HPA生理学研究中的应用，无论是在基础还是动态条件下。
