Ikeda Yukio, Iguchi Haruhisa, Nakata Masanori, Ioka Ryoichi X, Tanaka Toshiya, Iwasaki Satoshi, Magoori Kenta, Takayasu Shinobu, Yamamoto Tokuo T, Kodama Tatsuhiko, Yada Toshihiko, Sakurai Takeshi, Yanagisawa Masashi, Sakai Juro
Yanagisawa Orphan Receptor Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Tokyo 135-0064, Japan.
Biochem Biophys Res Commun. 2005 Aug 5;333(3):778-86. doi: 10.1016/j.bbrc.2005.06.005.
The glucose-induced insulin secretion is fine-tuned by numerous factors. To systematically identify insulinotropic factors, we optimized a primary beta-cell-based functional assay to monitor intracellular Ca2+ flux ([Ca2+]i). By this assay system, we successfully identified several insulinotropic peptides including cholecystokinin, gastrin releasing peptide, vasopressin, and oxytocin from tissue extracts. Screening of an assortment of chemical compounds, we determined three novel insulin secretagogues: N-arachidonylglycine (NAGly), 3beta-(2-diethylamino-ethoxy) androstenone hydrochloride (U18666A), and 4-androstene-3,17-dione. The NAGly increased [Ca2+]i through stimulation of the voltage-dependent Ca2+ channels and it was dependent on extracellular glucose level. On the other hand, U18666A and 4-androstene-3,17-dione increased [Ca2+]i in the presence of K ATP channel opener diazoxide while it was inhibited by the presence of Ca2+ channel blocker nitrendipine, suggesting that their effects are independent of K ATP channel. These unique features will be useful for further development of insulinotropic factors and drugs for treating type 2 diabetes.
葡萄糖诱导的胰岛素分泌受到多种因素的精细调节。为了系统地鉴定促胰岛素分泌因子，我们优化了一种基于原代β细胞的功能检测方法，以监测细胞内Ca2+通量（[Ca2+]i）。通过该检测系统，我们成功地从组织提取物中鉴定出了几种促胰岛素分泌肽，包括胆囊收缩素、胃泌素释放肽、血管加压素和催产素。在筛选各种化合物时，我们确定了三种新型胰岛素促分泌剂：N-花生四烯酰甘氨酸（NAGly）、3β-(2-二乙氨基乙氧基)雄烯酮盐酸盐（U18666A）和4-雄烯-3,17-二酮。NAGly通过刺激电压依赖性Ca2+通道增加[Ca2+]i，且其作用依赖于细胞外葡萄糖水平。另一方面，U18666A和4-雄烯-3,17-二酮在存在KATP通道开放剂二氮嗪的情况下增加[Ca2+]i，而在存在Ca2+通道阻滞剂尼群地平的情况下受到抑制，这表明它们的作用独立于KATP通道。这些独特的特性将有助于促胰岛素分泌因子和治疗2型糖尿病药物的进一步开发。
