Department of Clinical Science, Islet Cell Physiology, University of Lund, Sweden.
Mol Cell Endocrinol. 2010 May 14;320(1-2):16-24. doi: 10.1016/j.mce.2010.01.030. Epub 2010 Feb 1.
The role of the newly discovered estrogen receptor GPR30 in islet physiology and pathophysiology is unclear. We examined GPR30 expression in relation to hormone secretion and possible anti-apoptotic effects in isolated mouse islets using the synthetic GPR30 ligand G-1. The mRNA and protein expression of GPR30 was analyzed by qPCR, Western blot and confocal microscopy. Hormone secretion and cAMP content were determined with RIA and apoptosis in islet cells with the Annexin-V method. GPR30 mRNA and protein expression was markedly higher in islets from females compared to male. This gender difference was not found for the genomic estrogen receptors ER alpha and ER beta, the ER alpha expression being 10-fold higher than ER beta in both genders. Confocal microscopy revealed abounden GPR30 expression in insulin, glucagon and somatostatin cells. Dose-response studies of G-1 vs 17beta-estradiol in isolated islets at 1 or 12 mM glucose showed an almost identical pattern in that both compounds increased insulin and inhibited glucagon and somatostatin secretion. ICI-182,780 and EM-652, potent antagonists of the 17beta-estradiol receptors (ER alpha and ER beta) did not influence the amplifying effect of G-1 or 17beta-estradiol on cAMP content or insulin secretion from isolated islets. Cytokine-induced (IL-1 beta+TNFalpha+INF gamma) apoptosis in islets, cultured for 24h at 5mM glucose, was almost abolished by G-1 or 17beta-estradiol treatment. Addition of ICI-182,780 or EM-652 did not affect this beneficial effect of G-1 or 17beta-estradiol. Taken together, our findings show that GPR30 is expressed in most islet endocrine cells. The synthetic GPR30 ligand G-1 mimics the non-genomic effects of 17beta-estradiol on islet hormone secretion, cAMP content in islets and its anti-apoptotic effects. G-1 or analogs thereof might be new potential candidates in the therapeutic strategy for type 2 diabetes in women.
新发现的雌激素受体 GPR30 在胰岛生理学和病理生理学中的作用尚不清楚。我们使用合成的 GPR30 配体 G-1 检查了 GPR30 表达与激素分泌的关系以及在分离的小鼠胰岛中的可能抗凋亡作用。通过 qPCR、Western blot 和共聚焦显微镜分析 GPR30 的 mRNA 和蛋白表达。用 RIA 测定胰岛细胞的激素分泌和 cAMP 含量，用 Annexin-V 法测定胰岛细胞的凋亡。与男性相比，女性胰岛中的 GPR30 mRNA 和蛋白表达明显更高。这种性别差异在基因组雌激素受体 ER alpha 和 ER beta 中没有发现，在两种性别中，ER alpha 的表达是 ER beta 的 10 倍。共聚焦显微镜显示胰岛素、胰高血糖素和生长抑素细胞中存在丰富的 GPR30 表达。在 1 或 12 mM 葡萄糖的分离胰岛中，G-1 与 17β-雌二醇的剂量反应研究表明，两种化合物均增加胰岛素并抑制胰高血糖素和生长抑素分泌，其模式几乎相同。ICI-182,780 和 EM-652 是 17β-雌二醇受体（ER alpha 和 ER beta）的有效拮抗剂，它们不影响 G-1 或 17β-雌二醇对分离胰岛中环磷酸腺苷含量或胰岛素分泌的放大作用。在 5mM 葡萄糖培养 24 小时的胰岛中，细胞因子诱导的（IL-1β+TNFα+INFγ）凋亡几乎被 G-1 或 17β-雌二醇处理所消除。添加 ICI-182,780 或 EM-652 对 G-1 或 17β-雌二醇的这种有益作用没有影响。总的来说，我们的研究结果表明 GPR30 在大多数胰岛内分泌细胞中表达。合成的 GPR30 配体 G-1 模拟了 17β-雌二醇对胰岛激素分泌、胰岛中环磷酸腺苷含量和抗凋亡作用的非基因组效应。G-1 或其类似物可能是女性 2 型糖尿病治疗策略中的新的潜在候选药物。
