Bahr N I, Pryce C R, Döbeli M, Martin R D
Anthropologisches Institut und Museum der Universität Zürich, Switzerland.
Physiol Behav. 1998 Jun 15;64(4):429-37. doi: 10.1016/s0031-9384(98)00057-2.
By studying western lowland gorillas (Gorilla gorilla gorilla, n = 8) in zoological gardens via ethological and non-invasive physiological techniques, we have demonstrated that their postpartum maternal behavior is related negatively to their postpartum urinary titers of cortisol. On the basis of this finding, it is proposed that postpartum stress contributes to disrupted maternal behavior in the gorilla in captivity. Morning urine samples were collected with a mean sampling interval of 1.6 days from Day 14 prepartum to Day 14 postpartum (n = 11 pregnancies). Creatinine-indexed (Cr) urinary cortisol titers declined significantly between Day 9 to 1 prepartum (0.634 +/- 0.014 microg/mg of Cr, mean +/- SEM) and Day 1 to 6 postpartum (0.396 +/- 0.030 microg/mg of Cr, mean +/- SEM; p < 0.01-0.001). For each pregnancy, the relative postpartum decline in urinary cortisol was calculated as (microg of cortisol/mg of Cr Day 1 to 4)/(microg of cortisol/mg of Cr Day -4 to -1). Values ranged from 0.35 to 1.12, were independent of absolute prepartum cortisol titers, and were interpreted as evidence of inter-female differences in postpartum hypothalamo-pituitary-adrenal axis activity and, therefore, postpartum stress. This postpartum stress index was negatively correlated with the amount of time (0-100%) that females carried and supported their 0-14 day-old infants in a ventral position during locomotion (r(s) = -0.68, p < 0.05) and tended to be negatively correlated with the total amount of time (0-100%) they spent in ventro-ventral contact with their infants (r(s) = -0.58; p < 0.10). This study provides the first physiological evidence that postpartum stress is an important etiologic factor in gorilla maternal failure in captive environments.
通过在动物园中运用行为学和非侵入性生理学技术研究西部低地大猩猩（Gorilla gorilla gorilla，n = 8），我们发现它们产后的母性行为与产后尿液中的皮质醇水平呈负相关。基于这一发现，有人提出产后应激是导致圈养大猩猩母性行为紊乱的原因。从产前14天到产后14天（n = 11次怀孕），每隔1.6天采集一次晨尿样本。肌酐校正后的（Cr）尿皮质醇水平在产前第9天到第1天（0.634±0.014微克/毫克Cr，平均值±标准误）和产后第1天到第6天（0.396±0.030微克/毫克Cr，平均值±标准误；p < 0.01 - 0.001）之间显著下降。对于每次怀孕，计算尿皮质醇的产后相对下降值为（产后第1至4天皮质醇微克/毫克Cr）/（产前第 - 4至 - 1天皮质醇微克/毫克Cr）。该值范围为0.35至1.12，与产前皮质醇的绝对水平无关，被解释为雌性间产后下丘脑 - 垂体 - 肾上腺轴活动差异的证据，因此也是产后应激的证据。这种产后应激指数与雌性在移动过程中以腹位携带和支撑其0至14日龄婴儿的时间量（0 - 100%）呈负相关（r(s) = -0.68，p < 0.05），并且倾向于与它们与婴儿腹 - 腹接触的总时间量（0 - 100%）呈负相关（r(s) = -0.58；p < 0.10）。本研究提供了首个生理学证据，表明产后应激是圈养环境中大猩猩母性失败的一个重要病因。
