Campbell Jonathan E, Rakhshani Nasimeh, Fediuc Sergiu, Bruni Silvio, Riddell Michael C
School of Kinesiology and Health Science,Toronto, ON, Canada.
J Appl Physiol (1985). 2009 Jan;106(1):66-72. doi: 10.1152/japplphysiol.91128.2008. Epub 2008 Nov 13.
Although exercise is a common and potent activator of the hypothalamic-pituitary adrenal (HPA) axis, the effects of exercise on the acute stress response are not well understood. Here, we investigated the effects of short- (2 wk) and long-term (8 wk) voluntary wheel running on adrenal sensitivity to ACTH stimulation and the acute stress response to restraint in male rats. Diurnal glucocorticoid patterns were measured on days 7 (all groups) and 35 (8-wk groups). Rats were subjected to 20 min of restraint stress on either week 1 or on week 7 of treatment to assess HPA activation. One week later, exogenous ACTH (75 ng/kg) was administered to assess adrenal sensitivity to ACTH. Following this, adrenals were collected and analyzed for key proteins involved in corticosterone (CORT) synthesis. By the end of week 1, exercising (E) animals had twofold higher peak diurnal CORT levels compared with sedentary (S) animals (P < 0.01). CORT values were not different between groups at week 8. In response to restraint stress at week 2, CORT values in E were approximately threefold greater than in S (P < 0.05). No difference was found between E and S rats in the response to, or recovery from, restraint at week 8. During the ACTH challenge at week 2, E demonstrated a approximately 2.5-fold increase in adrenal sensitivity compared with S, while no difference was found between E and S at week 8. The expression of steroidogenic acute regulatory protein was found to be approximately 50% higher in the adrenals in E compared with S at week 2 (P < 0.05), but no difference existed between groups at week 8. These results show that volitional wheel running initially causes hyperactivation of the HPA axis, due to enhanced adrenal sensitivity to ACTH, but that these alterations in HPA activity are completely restored by 8 wk of training.
尽管运动是下丘脑-垂体-肾上腺（HPA）轴常见且有效的激活因素，但运动对急性应激反应的影响尚未完全明确。在此，我们研究了短期（2周）和长期（8周）自愿轮转运动对雄性大鼠肾上腺对促肾上腺皮质激素（ACTH）刺激的敏感性以及对束缚应激的急性应激反应的影响。在第7天（所有组）和第35天（8周组）测量昼夜糖皮质激素模式。在治疗的第1周或第7周，对大鼠施加20分钟的束缚应激以评估HPA轴的激活情况。一周后，给予外源性ACTH（75 ng/kg）以评估肾上腺对ACTH的敏感性。此后，收集肾上腺并分析参与皮质酮（CORT）合成的关键蛋白。到第1周结束时，与久坐不动（S）的动物相比，运动（E）的动物昼夜CORT峰值水平高出两倍（P < 0.01）。第8周时，各组之间的CORT值没有差异。在第2周对束缚应激的反应中，E组的CORT值比S组大约高三倍（P < 0.05）。在第8周，E组和S组大鼠对束缚应激的反应或恢复情况没有差异。在第2周的ACTH刺激试验中，与S组相比，E组肾上腺敏感性增加约2.5倍，而在第8周，E组和S组之间没有差异。在第2周时，发现E组肾上腺中类固醇生成急性调节蛋白的表达比S组高出约50%（P < 0.05），但在第8周时，各组之间没有差异。这些结果表明，自愿轮转运动最初会导致HPA轴过度激活，这是由于肾上腺对ACTH的敏感性增强，但通过8周的训练，HPA活动的这些改变会完全恢复。
