Peschke E, Peschke D, Hammer T, Csernus V
Department of Anatomy and Cell Biology, Martin Luther University, Halle-Wittenberg, Germany.
J Pineal Res. 1997 Oct;23(3):156-63. doi: 10.1111/j.1600-079x.1997.tb00349.x.
Insulin plays a key role in the control of glucose homeostasis in mammals. Insulin secretion is regulated by a coordinated interplay of several factors. The role of the indoleamines in the control of insulin secretion has not been fully elucidated yet. The present study was addressed to investigate the function of melatonin and serotonin in the direct control of insulin secretion from the pancreatic islets. Explanted rat Langerhans' islets were treated with melatonin or serotonin while also being exposed to specific (glucose) or non-specific (KCl) stimulus either in a pulsatile or long-term manner in a perifusion system. Insulin content from the effluent tissue culture media was analyzed with RIA. Pulsatile administration of melatonin and serotonin alone did not alter the basal insulin secretion from the explanted islets even at pharmacological (5 microM) level. However, insulin response to specific (glucose) or non-specific (KCl) stimulus was significantly reduced while the islets were treated with melatonin (3 to 12 hr, 10 nM to 5 microM). This effect was reversible and repeatable. Both the start and end of the effect was rapid, evolving and disappearing within 10 min. On the other hand, under similar experimental protocol, serotonin (at 5 microM concentration) significantly enhanced both glucose and KCl stimulated insulin release. Since the effect of the non-specific stimulation (with KCl) was also altered, melatonin and serotonin seem to alter not only the release but also the synthesis of the insulin. Our data show that melatonin and serotonin have a direct effect on the insulin secretion from the pancreatic islets.
胰岛素在哺乳动物血糖稳态的控制中起着关键作用。胰岛素分泌受多种因素的协同相互作用调节。吲哚胺在胰岛素分泌控制中的作用尚未完全阐明。本研究旨在探讨褪黑素和血清素对胰岛胰岛素分泌的直接控制作用。将分离出的大鼠胰岛用褪黑素或血清素处理，同时在灌流系统中以脉冲或长期方式使其暴露于特定（葡萄糖）或非特异性（氯化钾）刺激。用放射免疫分析法分析流出的组织培养基中的胰岛素含量。单独脉冲给予褪黑素和血清素即使在药理学（5微摩尔）水平也不会改变分离出的胰岛的基础胰岛素分泌。然而，当胰岛用褪黑素（3至12小时，10纳摩尔至5微摩尔）处理时，对特定（葡萄糖）或非特异性（氯化钾）刺激的胰岛素反应显著降低。这种作用是可逆的且可重复的。作用的开始和结束都很快，在10分钟内出现并消失。另一方面，在类似的实验方案下，血清素（浓度为5微摩尔）显著增强了葡萄糖和氯化钾刺激的胰岛素释放。由于非特异性刺激（用氯化钾）的作用也发生了改变，褪黑素和血清素似乎不仅改变胰岛素的释放，还改变其合成。我们的数据表明，褪黑素和血清素对胰岛胰岛素分泌有直接影响。
