Glucose metabolism in ghrelin conditional KO mice

据报道，Ghrelin通过Gi蛋白限制胰岛b细胞中胰岛素的释放，从而调节血糖稳态。本研究探讨了Ghrelin是否调节cAMP信号，以及这种调节是否诱导胰岛b细胞的胰岛素静止级联反应。此外，本研究旨在阐明Ghrelin是否能拮抗GLP-1的作用，GLP-1是一种促进葡萄糖诱导的大鼠胰岛b细胞胰岛素释放的生理性生长素激素。Ghrelin直接与b细胞相互作用，抑制葡萄糖诱导的cAMP产生和PKA激活，从而激活Kv通道，抑制葡萄糖诱导的[Ca~(2+)]i升高和胰岛素释放。Ghrelin可有效抑制GLP-1诱导的b细胞cAMP生成、[Ca~(2+)]i升高和胰岛素释放。这些结果表明，Ghrelin和GLP-1之间的相互作用在葡萄糖诱导的胰岛素释放的生理调节中起着重要作用。

Ghrelin reportedly restricts insulin release in islet b-cells via Gi-proteins and thereby regulates glucose homeostasis. This study explored whether ghrelin regulates cAMP signaling and whether this regulation induces insulinostatic cascade in islet b-cells. Furthermore, this study aimed to clarify whether ghrelin counteracts effects of GLP-1, a physiological incretin hormone that promote glucose-induced insulin release in rat islet b-cells.Ghrelin directly interacts with b-cells to attenuate glucose-induced cAMP production and PKA activation, which lead to activation of Kv channels and suppression of glucose-induced [Ca2+]i increase and insulin release. Ghrelin potently attenuates GLP-1-induced cAMP production, [Ca2+]i increases and insulin release in b-cells. These findings indicate that interaction between ghrelin and GLP-1 plays an important role in physiological regulation of glucose-induced insulin release.