Heistermann M, Palme R, Ganswindt A
Department of Reproductive Biology, German Primate Center, Göttingen, Germany.
Am J Primatol. 2006 Mar;68(3):257-73. doi: 10.1002/ajp.20222.
Most studies published to date that used fecal glucocorticoid measurements to assess adrenocortical activity in primate (and many nonprimate) species applied a specific cortisol or corticosterone assay. However, since these native glucocorticoids are virtually absent in the feces of most vertebrates, including primates, the validity of this approach has recently been questioned. Therefore, the overall aim of the present study was to assess the validity of four enzyme-immunoassays (EIAs) using antibodies raised against cortisol, corticosterone, and reduced cortisol metabolites (two group-specific antibodies) for assessing adrenocortical activity using fecal glucocorticoid metabolite (GCM) measurements in selected primate species (marmoset, long-tailed macaque, Barbary macaque, chimpanzee, and gorilla). Using physiological stimulation of the hypothalamo-pituitary-adrenocortical (HPA) axis by administering exogenous ACTH or anesthesia, we demonstrated that at least two assays detected the predicted increase in fecal GCM levels in response to treatment in each species. However, the magnitude of response varied between assays and species, and no one assay was applicable to all species. While the corticosterone assay generally was of only limited suitability for assessing glucocorticoid output, the specific cortisol assay was valuable for those species that (according to high-performance liquid chromatography (HPLC) analysis data) excreted clearly detectable amounts of authentic cortisol into the feces. In contrast, in species in which cortisol was virtually absent in the feces, group-specific assays provided a much stronger signal, and these assays also performed well in the other primate species tested (except the marmoset). Collectively, the data suggest that the reliability of a given fecal glucocorticoid assay in reflecting activity of the HPA axis in primates clearly depends on the species in question. Although to date there is no single assay system that can be used successfully across species, our data suggest that group-specific assays have a high potential for cross-species application. Nevertheless, regardless of which GC antibody is chosen, our study clearly reinforces the necessity of appropriately validating the respective assay system before it is used.
迄今为止发表的大多数研究，在评估灵长类动物（以及许多非灵长类动物）的肾上腺皮质活动时，都采用粪便糖皮质激素测量方法，并应用了特定的皮质醇或皮质酮检测方法。然而，由于包括灵长类动物在内的大多数脊椎动物的粪便中几乎不存在这些天然糖皮质激素，这种方法的有效性最近受到了质疑。因此，本研究的总体目标是评估四种酶免疫分析（EIA）方法的有效性，这些方法使用针对皮质醇、皮质酮和还原型皮质醇代谢物（两种组特异性抗体）产生的抗体，通过测量选定灵长类动物物种（狨猴、食蟹猴、巴巴里猕猴、黑猩猩和大猩猩）的粪便糖皮质激素代谢物（GCM）来评估肾上腺皮质活动。通过给予外源性促肾上腺皮质激素（ACTH）或麻醉对下丘脑-垂体-肾上腺皮质（HPA）轴进行生理刺激，我们证明，至少有两种检测方法能检测到每种物种粪便GCM水平因治疗而出现的预期升高。然而，不同检测方法和物种之间的反应程度有所不同，没有一种检测方法适用于所有物种。虽然皮质酮检测方法通常仅在有限程度上适用于评估糖皮质激素输出，但特定的皮质醇检测方法对于那些（根据高效液相色谱（HPLC）分析数据）粪便中排泄出明显可检测量的真实皮质醇的物种很有价值。相比之下，在粪便中几乎不存在皮质醇的物种中，组特异性检测方法提供了更强的信号，并且这些检测方法在其他受试灵长类动物物种（除狨猴外）中也表现良好。总体而言，数据表明，特定粪便糖皮质激素检测方法在反映灵长类动物HPA轴活动方面的可靠性显然取决于所研究的物种。虽然迄今为止还没有一种能成功应用于所有物种的单一检测系统，但我们的数据表明，组特异性检测方法具有很高的跨物种应用潜力。然而，无论选择哪种糖皮质激素抗体，我们的研究都明确强调了在使用各自的检测系统之前进行适当验证的必要性。
