Neurosciences Centre of Excellence for Drug Discovery, GlaxoSmithKline, Medicines Research Centre, 37135 Verona, Italy.
Eur J Pharmacol. 2011 Jan 10;650(1):178-83. doi: 10.1016/j.ejphar.2010.10.042. Epub 2010 Oct 29.
A novel growth hormone secretagogues type 1a (GHS1a) receptors antagonist (2R)-N'-[3,5- bis(trifluoromethyl)phenyl]-2-[(8aR)-hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]-2-(3- pyridinyl)ethanohydrazide (GSK1614343) was functionally characterised in rat pituitary adenoma cell line, RC-4B/C endogenously expressing GHS1a receptors. The antagonism profile of GSK1614343 was compared with that of 6-[(4-fluorophenyl)oxy]-2-methyl-3-{[(3S)-1-(1-methylethyl)-3- piperidinyl]methyl}-4(3H)-quinazolinone (YIL-781) another ghrelin receptor antagonist recently published. The activity of both compounds was also evaluated at rat recombinant GHS1a receptors. The characterization of the two antagonists was performed by intracellular calcium mobilization measurements by using fluorometric imaging plate reader (FLIPR) technology and inositol phosphate (IP) turnover measurements by [3H]-IP accumulation assay. RC-4B/C and U2-OS cells transiently transduced with rat GHS1a receptors virus were used. In RC-4B/C cells, GSK1614343 and YIL-781, depressed the ghrelin maximal response in FLIPR assay as result of hemi-equilibria phenomenon. When using the [3H]-IP accumulation assay both compounds behaved as competitive antagonist with pKB values of 8.03 for GSK1614343 and 7.54 for YIL-781. In rat recombinant receptor, GSK1614343 and YIL-781 inhibited the calcium response induced by ghrelin with pIC50 values of 7.90 and 8.27, respectively. GSK1614343 and YIL-781 did not show intrinsic activity in both endogenously expressed and recombinant rat GHS1a receptors. The new ghrelin receptor antagonist GSK1614343 is a potent competitive antagonist in rat pituitary RC-4B/C cells endogenously expressing GHS1a receptors when equilibrium conditions between ligand and receptor are reached in the test assay. GSK1614343 represents a useful tool to investigate the physiological relevance of the ghrelin system in rat models.
一种新型生长激素促分泌素 1a 型（GHS1a）受体拮抗剂（2R）-N'-[3,5- 双（三氟甲基）苯基]-2-[[8aR]-六氢吡咯并[1,2-a]吡嗪-2（1H）-基]-2-（3-吡啶基）乙脒（GSK1614343）在大鼠垂体腺瘤细胞系 RC-4B/C 中进行了功能表征，该细胞系内源性表达 GHS1a 受体。GSK1614343 的拮抗谱与最近发表的另一种胃饥饿素受体拮抗剂 6-[[4-氟苯基]氧基]-2-甲基-3-[[（3S）-1-（1-甲基乙基）-3-哌啶基]甲基]-4（3H）-喹唑啉酮（YIL-781）进行了比较。还评估了这两种化合物在大鼠重组 GHS1a 受体上的活性。使用荧光成像板读取器（FLIPR）技术通过细胞内钙动员测量和[3H]-肌醇磷酸盐（IP）积累测定通过 IP 转换测量来进行两种拮抗剂的表征。使用 RC-4B/C 和 U2-OS 细胞瞬时转导大鼠 GHS1a 受体病毒。在 RC-4B/C 细胞中，GSK1614343 和 YIL-781 通过半平衡现象抑制了 FLIPR 测定中胃饥饿素的最大反应，表明其为半效平衡现象。当使用[3H]-IP 积累测定时，两种化合物均表现为竞争性拮抗剂，pKB 值分别为 GSK1614343 的 8.03 和 YIL-781 的 7.54。在大鼠重组受体中，GSK1614343 和 YIL-781 抑制了 ghrelin 诱导的钙反应，pIC50 值分别为 7.90 和 8.27。GSK1614343 和 YIL-781 在内源性表达和重组大鼠 GHS1a 受体中均没有表现出内在活性。当在测试中达到配体和受体之间的平衡条件时，新型胃饥饿素受体拮抗剂 GSK1614343 是大鼠垂体 RC-4B/C 细胞中内源表达的 GHS1a 受体的有效竞争性拮抗剂。GSK1614343 是一种有用的工具，可以在大鼠模型中研究胃饥饿素系统的生理相关性。
