Rangel-Negrín Ariadna, Flores-Escobar Elizabeth, Chavira Roberto, Canales-Espinosa Domingo, Dias Pedro Américo D
Instituto de Neuroetología, Universidad Veracruzana, Av. Dr. Luis Castelazo Ayala S/N, Industrial Animas, 91190, Xalapa, Mexico,
Primates. 2014 Oct;55(4):459-65. doi: 10.1007/s10329-014-0432-4. Epub 2014 Jun 18.
The measurement of hormones in fecal samples allows for the noninvasive assessment of the endocrine status of free-ranging primates. However, procedures and techniques for hormone analysis in feces must be validated, both analytically and physiologically. Few studies have addressed the endocrinology of black howler monkeys (Alouatta pigra). Due to its conservation status, direct handling of individuals from this species and invasive sample collection are highly regulated, and therefore traditional methods for the validation of hormone assays, such as pharmacological challenges, are not allowed. As a consequence, sometimes studies of the fecal hormones of free-ranging black howler monkeys do not report physiological validations and therefore the biological reliability of such measurements cannot be assessed. In order to stimulate future research with this species, the present study aimed at providing methodological bases for fecal endocrine monitoring. Specifically, we compared the validity of two immunoassays (radioimmunoassays, RIA; solid-phase chemiluminescent enzyme immunoassay, SPCEI) performed with commercial kits to measure cortisol, testosterone, estradiol, and progesterone; and demonstrate how the physiological functions of these steroid hormones can be determined through non-pharmacological validations. We found no differences between the analytical validity of RIA and SPCEI assays to measure cortisol and testosterone, whereas for estradiol and progesterone RIA showed better results. Concerning the physiological validation of our assays, we demonstrated that: (1) comparisons between pre- and post-stress situations may be used to assess cortisol response, (2) comparisons between females and males may be used to assess variation in testosterone levels, and (3) comparisons between pregnant and non-pregnant females may be used to determine variation in estradiol and progesterone activity. The analytical and physiological validations that we performed demonstrate that there are currently commercial kits that allow for correct endocrine monitoring of this species, and that there are non-pharmacological alternatives to assess the biological validity of hormone measurements.
对粪便样本中的激素进行测量，有助于对野生灵长类动物的内分泌状态进行非侵入性评估。然而，粪便中激素分析的程序和技术必须在分析和生理方面都得到验证。很少有研究涉及黑吼猴（Alouatta pigra）的内分泌学。由于其保护地位，对该物种个体的直接处理和侵入性样本采集受到严格监管，因此传统的激素检测验证方法，如药理学激发试验，是不被允许的。因此，有时对野生黑吼猴粪便激素的研究没有报告生理验证情况，所以无法评估此类测量的生物学可靠性。为了推动对该物种未来的研究，本研究旨在为粪便内分泌监测提供方法学基础。具体而言，我们比较了使用商业试剂盒进行的两种免疫测定法（放射免疫测定法，RIA；固相化学发光酶免疫测定法，SPCEI）测量皮质醇、睾酮、雌二醇和孕酮的有效性；并展示了如何通过非药理学验证来确定这些类固醇激素的生理功能。我们发现，在测量皮质醇和睾酮时，RIA和SPCEI测定法的分析有效性没有差异，而对于雌二醇和孕酮，RIA显示出更好的结果。关于我们测定法的生理验证，我们证明：（1）应激前后情况的比较可用于评估皮质醇反应，（2）雌性和雄性之间的比较可用于评估睾酮水平的变化，（3）怀孕和未怀孕雌性之间的比较可用于确定雌二醇和孕酮活性的变化。我们进行的分析和生理验证表明，目前有商业试剂盒可对该物种进行正确的内分泌监测，并且存在非药理学方法来评估激素测量的生物学有效性。
