Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, Hannover 30559, Germany.
Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, Hannover 30559, Germany.
Vet J. 2024 Aug;306:106172. doi: 10.1016/j.tvjl.2024.106172. Epub 2024 Jun 21.
In insulin dysregulation, hyperinsulinemia (HI) can be accompanied by peripheral insulin resistance (IR) in horses, which can be diagnosed with an insulin-tolerance test (ITT). The administration of 0.1 IU/kg body weight of recombinant regular human insulin (RHI) should elicit a 50 % reduction of the initial blood glucose concentration at 30 min after insulin administration in insulin sensitive horses. Compared to RHI, porcine zinc insulin (PZI) is veterinary-approved and therefore easier accessible for many practitioners. The aim of this study was to compare the insulin and glucose dynamics during a standard ITT with RHI to an ITT performed with PZI. Twelve Icelandic horses were subjected to an ITT with RHI (ITT-RHI) and with PZI (ITT-PZI) at same dosages in a randomised crossover design. The insulin and glucose dynamics that resulted from these tests were compared, and the consistency of classification into insulin-sensitive and IR categories was evaluated. No complications were observed with the use of either RHI or PZI in ITT. A good correlation of the test results was observed (r = 0.88; P < 0.001). The blood glucose concentrations and the percentage reduction in glucose concentration did not differ significantly between the two tests (P = 0.053), but four out of twelve horses were classified as IR in the ITT-RHI whereas with the ITT-PZI seven out of twelve horses were classified as IR with the 50 % glucose reduction from baseline. Based on the Youden index, when using the ITT-PZI, an adjusted cut-off value for blood glucose reduction of 40 % at 30 min resulted in better test performance. With consideration for the seemingly weaker effect of PZI and the adjusted cut-off value, PZI can be an appropriate substitute to RHI in an ITT.
在胰岛素失调中，高胰岛素血症（HI）可伴有马外周胰岛素抵抗（IR），可通过胰岛素耐量试验（ITT）进行诊断。在胰岛素敏感的马匹中，给予 0.1IU/kg 体重的重组人常规胰岛素（RHI）后，应在胰岛素给药后 30 分钟使初始血糖浓度降低 50%。与 RHI 相比，猪胰岛素锌（PZI）已获得兽医批准，因此对许多从业者来说更容易获得。本研究的目的是比较使用 RHI 和 PZI 进行标准 ITT 时的胰岛素和血糖动态，并评估将马匹分类为胰岛素敏感和 IR 类别的一致性。在随机交叉设计中，12 匹冰岛马接受了 RHI（ITT-RHI）和 PZI（ITT-PZI）的 ITT，剂量相同。比较了这些测试产生的胰岛素和血糖动态，并评估了将马匹分类为胰岛素敏感和 IR 类别的一致性。在 ITT 中使用 RHI 或 PZI 均未观察到并发症。测试结果具有良好的相关性（r = 0.88；P < 0.001）。两种测试的血糖浓度和葡萄糖浓度降低百分比没有显著差异（P = 0.053），但在 ITT-RHI 中，12 匹马中有 4 匹被归类为 IR，而在 ITT-PZI 中，12 匹马中有 7 匹被归类为 IR，与基线相比，血糖降低了 50%。基于 Youden 指数，当使用 ITT-PZI 时，30 分钟时血糖降低 40%的调整截断值可获得更好的测试性能。考虑到 PZI 的作用似乎较弱以及调整后的截断值，PZI 可以作为 ITT 中 RHI 的合适替代品。
