Comparison of glucose tolerance between wild-type mice and mice with double knockout of neuromedin U and neuromedin S
Comparison of glucose tolerance between wild-type mice and mice with double knockout of neuromedin U and neuromedin S
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DOI：
10.1292/jvms.19-0320
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发表时间：
2019-09-01
影响因子：
1.2
通讯作者：
Nakahara, Keiko
中科院分区：
文献类型：
--
作者：
Ensho, Takuya;Maruyama, Keisuke;Nakahara, Keiko
最近，有人提出神经调节素U（NMU）是“促胰岛素”，在体外抑制胰腺的胰岛素分泌。在这里，我们通过将野生型小鼠的血浆葡萄糖和胰岛素水平与 NMU 和神经调节素 S (NMS) 基因双敲除 (D-KO) 小鼠的血浆葡萄糖和胰岛素水平进行比较，研究了 NMU 在体内胰岛素分泌中的可能参与，因为 NMS 与神经调节素 U 受体结合。如果 NMU 实际上是抑制胰腺胰岛素分泌的“促胰岛素”，那么缺乏 NMU 的小鼠可能会导致血浆胰岛素水平高于野生型小鼠，或者注射 NMU 会导致血浆胰岛素水平受到抑制。在这项研究中，我们发现 D-KO 小鼠的空腹血浆胰岛素水平没有增加。葡萄糖耐量测试显示，在非禁食条件下，野生型小鼠和D-KO小鼠的血浆胰岛素水平没有显着差异。外周注射 NMU 后，野生型或 D-KO 小鼠的血浆葡萄糖和胰岛素水平均未显示出任何显着变化。高脂肪喂养 3 周后的葡萄糖耐量测试显示，注射葡萄糖后 60 分钟内，野生型小鼠和 D-KO 小鼠的血浆胰岛素水平没有显着差异。这些结果表明，即使 NMU 是一种候选促胰岛素，其在体内抑制胰岛素分泌的生理作用也可能非常小。
Recently, it has been proposed that neuromedin U (NMU) is "decretin", which suppresses insulin secretion from the pancreas in vitro. Here we examined the possible involvement of NMU in insulin secretion in vivo by comparing the plasma glucose and insulin levels of wild-type mice with those of double knockout (D-KO) of the NMU and neuromedin S (NMS) genes, as NMS binds to the neuromedin U receptor. If NMU is, in fact, "decretin", which inhibits insulin secretion from the pancreas, then NMU-deficient mice might result in higher plasma insulin levels than is the case in wild-type mice, or injection of NMU lead to suppression of plasma insulin level. In this study, we found that the fasting plasma level of insulin was not increased in D-KO mice. Glucose tolerance tests revealed no significant difference in plasma insulin levels between wild-type mice and D-KO mice under non-fasting conditions. After peripheral injection of NMU, plasma glucose and insulin levels did not show any significant changes in either wild-type or D-KO mice. Glucose tolerance testing after 3 weeks of high fat feeding revealed no significant difference in plasma insulin levels during 60 min after glucose injection between wild-type and D-KO mice. These results suggest that even if NMU is a decretin candidate, its physiological involvement in suppression of insulin secretion may be very minor in vivo.