Faculty of Natural Resources, Agriculture and Veterinary Science, University of Queensland, Gatton, Australia.
Equine Vet J. 2013 Jan;45(1):66-73. doi: 10.1111/j.2042-3306.2012.00575.x. Epub 2012 May 6.
The sensitivity and specificity of basal plasma α-melanocyte-stimulating hormone (α-MSH) and adrenocorticotrophic hormone (ACTH) for the diagnosis of pituitary pars intermedia dysfunction (PPID) has not been evaluated in a population-based study.
To evaluate basal plasma α-MSH and ACTH concentrations for the diagnosis of PPID in a population of horses aged ≥ 15 years.
Owner-reported data were obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners was visited and veterinary examination performed on horses aged ≥ 15 years. Blood samples were analysed for plasma α-MSH and ACTH concentrations. Seasonally adjusted cut-off values for α-MSH and ACTH concentrations for the diagnosis of PPID were obtained using Youden index values against a clinical gold standard diagnosis (hirsutism plus 3 or more clinical signs of PPID).
α-melanocyte-stimulating hormone and ACTH were highly correlated with each other and with clinical and historical indicators of PPID. The increase in both α-MSH and ACTH with increasing numbers of clinical signs in affected horses supports a spectrum of disease. Both variables were affected by season, with derived cut-off values being higher in autumn compared with other seasons. Sensitivity and specificity were moderate and good in nonautumn seasons (59 and 93%, respectively) for α-MSH using a cut-off of 52.0 pmol/l. Sensitivity and specificity were good in nonautumn seasons (80 and 83%, respectively) for ACTH using a cut-off of 29.7 pg/ml. For both α-MSH and ACTH, sensitivity and specificity were close to 100% for samples obtained during the autumn period.
Basal plasma α-MSH and ACTH had moderate-to-good sensitivity and specificity for the diagnosis of PPID, which improved substantially during the autumn period, suggesting this may be the ideal time to test. Further studies to develop seasonally adjusted reference intervals for different geographical locations are warranted.
尚未在基于人群的研究中评估基础血浆 α-黑素细胞刺激素 (α-MSH) 和促肾上腺皮质激素 (ACTH) 对脑垂体中叶功能减退症 (PPID) 的诊断敏感性和特异性。
评估≥15 岁马群中基础血浆 α-MSH 和 ACTH 浓度对 PPID 的诊断价值。
通过邮寄问卷的方式从马术团体中获得了主人报告的数据。对接受调查的主人的一个子组进行了访问，并对≥15 岁的马进行了兽医检查。分析了血液样本中的血浆 α-MSH 和 ACTH 浓度。使用 Youden 指数值针对临床金标准诊断（多毛症加 3 种或更多 PPID 临床症状）获得了季节性调整的 α-MSH 和 ACTH 浓度诊断 PPID 的截断值。
α-MSH 和 ACTH 彼此高度相关，与 PPID 的临床和历史指标也高度相关。受影响的马随着临床体征数量的增加，α-MSH 和 ACTH 均增加，支持疾病谱的存在。这两个变量都受季节的影响，在秋季与其他季节相比，得出的截断值更高。在非秋季季节，α-MSH 的截断值为 52.0 pmol/l 时，敏感性和特异性分别为中等和良好（分别为 59%和 93%）。在非秋季季节，ACTH 的截断值为 29.7 pg/ml 时，敏感性和特异性均为良好（分别为 80%和 83%）。对于 α-MSH 和 ACTH，在秋季获得的样本中，敏感性和特异性均接近 100%。
基础血浆 α-MSH 和 ACTH 对诊断 PPID 的敏感性和特异性为中等至良好，在秋季时显著提高，这表明这可能是测试的理想时间。需要进一步研究以针对不同地理位置制定季节性调整的参考区间。
