Non-invasive measures of stress are crucial for captive and conservation management programs. The adrenal hormone dehydroepiandrosterone-sulfate (DHEAS) has recently been adopted as a stress marker, but there is little investigation of its relationship to glucocorticoids (GC), well-known indicators of stress. This study examined the influence of age, reproductive state and environment on GC and DHEAS levels in orangutans, to test whether the GC/DHEAS ratio can provide an index of stress response in primates. We measured fecal GC (fGC) and fecal DHEAS (fDHEAS) concentrations in 7 captive orangutans from zoological parks in Japan and 22 wild orangutans from Danum Valley Conservation Area, Malaysia. We found that in a stressful condition (transportation), fDHEAS levels increased 2 days after the fGC response, which occurred 1 day after the stressor. One pregnant female had elevated levels of both hormones, and a higher fGC/fDHEAS ratio than baseline. Females in the first year of lactation had fGC levels and the fGC/fDHEAS ratio significantly higher than both baseline and females in the second and subsequent years of lactation. There was no effect of age on fGC levels, but the fGC/fDHEAS ratio was higher in infants than adults and adolescents. fDHEAS concentrations were lower in infants than juveniles, adolescents and adults, a phenomenon known as adrenarche, shared with humans and other great apes. We suggest that changes in DHEAS during orangutan life history are associated with changes in the dynamics of maintaining homeostasis that vary with age and reproductive state. The GC/DHEAS ratio index is useful to evaluate age-related abilities of responding to stressful challenges.

中文翻译：

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猩猩（Pongo pygmaeus）内分泌应激反应的发育变化

非侵入性压力措施对于圈养和保护管理计划至关重要。肾上腺激素硫酸脱氢表雄酮 (DHEAS) 最近已被用作压力标记物，但对其与众所周知的压力指标糖皮质激素 (GC) 的关系的研究很少。本研究考察了年龄、生殖状态和环境对猩猩GC和DHEAS水平的影响，以测试GC/DHEAS比率是否可以提供灵长类动物应激反应的指标。我们测量了来自日本动物园的 7 只圈养猩猩和来自马来西亚丹浓谷保护区的 22 只野生猩猩的粪便 GC (fGC) 和粪便 DHEAS (fDHEAS) 浓度。我们发现在压力条件下（运输），fDHEAS 水平在 fGC 反应后 2 天增加，这发生在压力源后 1 天。一名怀孕女性的两种激素水平均升高，fGC/fDHEAS 比值高于基线。哺乳期第一年的雌性具有 fGC 水平，fGC/fDHEAS 比率显着高于哺乳期第二年和后续年的基线和雌性。年龄对 fGC 水平没有影响，但婴儿的 fGC/fDHEAS 比值高于成人和青少年。婴儿的 fDHEAS 浓度低于青少年、青少年和成人，这种现象被称为肾上腺皮质激素，与人类和其他类人猿共有。我们认为，猩猩生活史中 DHEAS 的变化与维持体内平衡的动态变化有关，这些动态随年龄和生殖状态而变化。GC/DHEAS 比率指数可用于评估与年龄相关的应对压力挑战的能力。