Departments of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden.
J Vet Diagn Invest. 2022 Jan;34(1):28-35. doi: 10.1177/10406387211052984. Epub 2021 Oct 26.
Catecholamine release increases in dogs with pheochromocytomas and in situations of stress. Although plasma catecholamines degrade rapidly, their metabolites, normetanephrine (NME) and metanephrine (ME), are stable in acidified urine. Our aim was to verify a human urine ELISA kit for the quantification of NME and ME in canine urine and to determine the effects on metabolite stability of sampling time (morning or midday) and day (ordinary or day spent in a clinic). We analyzed 179 urine samples from 17 healthy dogs. For NME, the mean intra-assay CV was 6.0% for all samples and 4.3% for the canine control; inter-assay CVs were 3.3, 3.8, and 12% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 90-101%. For ME, mean intra-assay CV was 6.5% for samples and 9.0% for the canine control; inter-assay CVs were 12.7, 7.2, and 22.5% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 85-89%. Dilution recovery was unsatisfactory for both metabolites. Based on our verification results, NME was selected for remaining analyses. We found no effect on NME concentrations of acidification or room temperature storage for up to 24 h. The NME:creatinine ratio was higher after the first of 3 clinic days compared to the same morning (111.2 ± 5.5 vs. 82.9 ± 5.3; < 0.0001), but not on the other days. NME verification results were generally superior to ME. Dilution studies were unsatisfactory for both metabolites. Given that NME was stable without acidification at room temperature, urine samples can be collected at home. The clinic environment can cause higher NME:creatinine ratios, especially in unaccustomed dogs.
儿茶酚胺释放增加在狗与嗜铬细胞瘤和在压力情况下。虽然血浆儿茶酚胺迅速降解，其代谢产物，去甲变肾上腺素（NME）和变肾上腺素（ME），在酸化尿液中稳定。我们的目的是验证人尿 ELISA 试剂盒定量检测犬尿中 NME 和 ME，并确定采样时间（上午或中午）和天（普通或在诊所度过的一天）对代谢物稳定性的影响。我们分析了 179 个来自 17 只健康狗的尿液样本。对于 NME，所有样本的平均批内 CV 为 6.0%，犬对照为 4.3%；试剂盒中提供的高、低浓度人尿阳性对照和阳性犬对照的批间 CV 分别为 3.3%、3.8%和 12%；回收率为 90-101%。对于 ME，样本的平均批内 CV 为 6.5%，犬对照为 9.0%；试剂盒中提供的高、低浓度人尿阳性对照和阳性犬对照的批间 CV 分别为 12.7%、7.2%和 22.5%；回收率为 85-89%。两种代谢物的稀释回收率都不理想。基于我们的验证结果，选择 NME 进行其余分析。我们发现酸化或室温储存长达 24 小时对 NME 浓度没有影响。与同一早晨（111.2 ± 5.5 比 82.9 ± 5.3； < 0.0001）相比，第 3 天的第一次就诊后，NME：肌酐比值较高，但在其他日子没有。NME 验证结果普遍优于 ME。稀释研究对两种代谢物都不理想。由于 NME 在室温下无需酸化即可稳定，因此可以在家中采集尿液样本。诊所环境可能会导致 NME：肌酐比值升高，尤其是在不习惯的狗中。
