Humphreys Sarah, Kass Philip H, Magdesian K Gary, Goodrich Erin, Berryhill Emily
School of Veterinary Medicine, University of California, Davis, Davis, CA, United States.
Department of Population Health and Reproduction, University of California, Davis, Davis, CA, United States.
Front Vet Sci. 2022 Aug 12;9:981920. doi: 10.3389/fvets.2022.981920. eCollection 2022.
Elevated plasma adrenocorticotropic hormone (ACTH) is often used to diagnose pituitary pars intermedia dysfunction (PPID) in horses. The hormone naturally increases in the fall in horses, and donkeys have been found to have higher ACTH concentrations than horses. However, circannual variation of ACTH has not been assessed in donkeys. The objective of the study was to establish seasonal variation of basal plasma ACTH concentrations over the course of a year in clinically healthy, non-geriatric donkeys. It was hypothesized that donkey ACTH concentrations would be higher than those reported in horses without PPID in all seasons, and that, similarly to horses, ACTH concentrations would further increase in the fall months. Twenty-six healthy adult donkeys (10 standards, 16 miniatures), a median (range) of 6 (2-13) years of age, were included. Donkeys were housed at a single location. Serial plasma samples were obtained monthly for 12 months. Plasma ACTH concentrations were determined by immunoassay. Data are presented as median (range), with a -value < 0.05 considered significant. ACTH concentrations were lowest in the winter and spring [12.8 (5.0-73.6) pg/ml and 12.5 (2.8-62.6) pg/ml, respectively], with an increase in the summer [53.2 (29.7-305.0) pg/ml], and peak in the fall [77.1 (12.4-319.0) pg/ml]. ACTH concentrations were highest in the month of September [122.0 (41.7-319.0) pg/ml]. Donkey ACTH concentrations were higher than equine reference ranges from May through November but showed similar circannual variation with dramatic increases in the fall months. Species-specific reference ranges are necessary for accurate interpretation of endocrinopathy screenings in donkeys.
血浆促肾上腺皮质激素（ACTH）升高常用于诊断马的垂体中间部功能障碍（PPID）。该激素在马体内秋季会自然升高，并且已发现驴的ACTH浓度高于马。然而，尚未评估驴ACTH的年周期变化。本研究的目的是确定临床健康、非老年驴在一年中基础血浆ACTH浓度的季节性变化。研究假设是，在所有季节中，驴的ACTH浓度都将高于无PPID的马所报告的浓度，并且与马相似，ACTH浓度在秋季月份会进一步升高。纳入了26头健康成年驴（10头标准体型，16头小型），年龄中位数（范围）为6（2 - 13）岁。驴饲养在单一地点。连续12个月每月采集血浆样本。通过免疫测定法测定血浆ACTH浓度。数据以中位数（范围）表示，P值<0.05被认为具有统计学意义。ACTH浓度在冬季和春季最低[分别为12.8（5.0 - 73.6）pg/ml和12.5（2.8 - 62.6）pg/ml]，夏季升高[53.2（29.7 - 305.0）pg/ml]，秋季达到峰值[77.1（12.4 - 319.0）pg/ml]。ACTH浓度在9月份最高[122.0（41.7 - 319.0）pg/ml]。从5月到11月，驴的ACTH浓度高于马的参考范围，但显示出类似的年周期变化，在秋季月份急剧增加。对于准确解释驴的内分泌病筛查结果，特定物种的参考范围是必要的。
