Marks J L, Waite K, Li M
Department of Clinical Endocrinology, Westmead Hospital, Australia.
Diabetologia. 1993 Jun;36(6):497-502. doi: 10.1007/BF02743264.
Levels of neuropeptide Y and neuropeptide Y mRNA are increased in the arcuate nucleus of severely diabetic rats which may be the result of the associated marked hypoinsulinaemia. We hypothesised that if neuropeptide Y mRNA is regulated by physiological changes in circulating insulin, then the relatively minor changes in circulating insulin found in mild diabetes would also affect neuropeptide Y expression and its response to changing insulin levels should be rapid. Neuropeptide Y mRNA was quantified by in situ hybridisation through the rostral, mid and caudal levels of the arcuate nucleus of adult female rats. Neuropeptide Y mRNA was significantly increased at all three levels of the arcuate nucleus, 7 days after i.v. administration of 40 mg/kg streptozotocin. Neuropeptide Y mRNA was not further increased in the arcuate nucleus of animals given 50 mg/kg streptozotocin. In the former group, serum glucose was increased but insulin levels and body weights were the same as in control rats. In the 50 mg/kg streptozotocin group, serum glucose was further increased while serum insulin and body weight were reduced. In addition, neuropeptide Y mRNA was not altered in the hypothalamic dorsomedial nucleus or the thalamic reticular nucleus. When diabetic rats were treated for 20 h with s.c. insulin, there was decreased neuropeptide Y mRNA in the arcuate nucleus. We conclude that neuropeptide Y mRNA in the arcuate nucleus is responsive to small changes in circulating insulin levels and the response occurs within 20 h. These data support that circulating insulin may contribute to control of neuropeptide Y expression under physiological conditions.
严重糖尿病大鼠弓状核中神经肽Y及其mRNA水平升高，这可能是伴有明显低胰岛素血症的结果。我们推测，如果神经肽Y mRNA受循环胰岛素生理变化的调节，那么轻度糖尿病中循环胰岛素相对较小的变化也会影响神经肽Y的表达，并且其对胰岛素水平变化的反应应该很快。通过原位杂交对成年雌性大鼠弓状核的嘴侧、中间和尾侧水平的神经肽Y mRNA进行定量。静脉注射40mg/kg链脲佐菌素7天后，弓状核所有三个水平的神经肽Y mRNA均显著增加。给予50mg/kg链脲佐菌素的动物，其弓状核中神经肽Y mRNA没有进一步增加。在前一组中，血糖升高，但胰岛素水平和体重与对照大鼠相同。在50mg/kg链脲佐菌素组中，血糖进一步升高，而血清胰岛素和体重降低。此外，下丘脑背内侧核或丘脑网状核中的神经肽Y mRNA没有改变。当糖尿病大鼠皮下注射胰岛素治疗20小时后，弓状核中的神经肽Y mRNA减少。我们得出结论，弓状核中的神经肽Y mRNA对循环胰岛素水平的微小变化有反应，且反应在20小时内发生。这些数据支持循环胰岛素在生理条件下可能有助于控制神经肽Y的表达。
