The physiological and psychological mechanisms explaining the individual variability in the stress response are poorly understood. We tested the hypothesis that hypothalamic-pituitary- adrenal (HPA) axis responses to colorectal stimulation affect HPA axis reactivity to corticotropin-releasing hormone (CRH), the visceral pain threshold, and perceived stress. We examined 31 healthy volunteers and 27 individuals with irritable bowel syndrome. According to the ACTH response to colorectal stimulation, the participants were classified into three groups: flattened, decreased, and increased. We found significant differences in the abdominal pain threshold, discomfort threshold, and sensitivity to anxiety among the groups. There were significant differences in the ACTH change and peak level after CRH administration among the groups. The area under the curve of the cortisol response to CRH was significantly different among the groups. The increased group showed a higher basal ACTH level, earlier peak level in the CRH administration test, and higher stress rating during the experiment. The increased group had an exaggerated psychological and physiological stress response, whereas the decreased group had a higher anticipatory endocrine response, stress, and sensitivity to anxiety. Further studies are needed to determine factors including gut microbiota on the individual difference in HPA response.

解释压力反应中个体差异的生理和心理机制知之甚少。我们检验了下丘脑-垂体-肾上腺 (HPA) 轴对结肠直肠刺激的反应影响 HPA 轴对促肾上腺皮质激素释放激素 (CRH) 的反应性、内脏痛阈和感知压力的假设。我们检查了 31 名健康志愿者和 27 名肠易激综合征患者。根据ACTH对结直肠刺激的反应，参与者被分为三组：扁平、减少和增加。我们发现各组之间的腹痛阈值、不适阈值和对焦虑的敏感性存在显着差异。CRH给药后ACTH变化和峰值水平各组间存在显着差异。各组间皮质醇对 CRH 反应的曲线下面积有显着差异。增加组表现出更高的基础ACTH水平，在CRH给药测试中更早的峰值水平，以及在实验过程中更高的压力等级。增加组有夸大的心理和生理应激反应，而减少组有更高的预期内分泌反应、压力和焦虑敏感性。需要进一步的研究来确定包括肠道微生物群在内的因素对 HPA 反应个体差异的影响。增加组有夸大的心理和生理应激反应，而减少组有更高的预期内分泌反应、压力和焦虑敏感性。需要进一步的研究来确定包括肠道微生物群在内的因素对 HPA 反应个体差异的影响。增加组有夸大的心理和生理应激反应，而减少组有更高的预期内分泌反应、压力和焦虑敏感性。需要进一步的研究来确定包括肠道微生物群在内的因素对 HPA 反应个体差异的影响。