Faculty of Medicine, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Pancreas. 2010 Mar;39(2):127-34. doi: 10.1097/MPA.0b013e3181bea475.
This study evaluated the role played by cholecystokinin (CCK) receptors' occupation in the control of somatostatin (SS) secretion in RIN-14B cells.
The presence of the CCK receptors 1 and 2 was confirmed by immunofluorescence, and SS secretion was evaluated by enzyme-linked immunosorbent assay.
By immunofluorescence, 95% of the cell population was composed of SS cells bearing both CCK-R subtypes with 5% of beta cells (data not shown). Cerulein (Cae), a CCK-1R agonist, and pentagastrin, a CCK-2R agonist, dose-dependently increased SS release, 3-fold at 1 mumol/L Cae, 2.5-fold at 10 mumol/L pentagastrin, with occupation of both CCKRs confirmed by L-364,178 and L-365,260 inhibition of CCK receptors 1 and 2. The occupation of high-affinity CCK-1R by Cae was confirmed on SS release with JMV-180, a high-affinity CCK-1R agonist, and absence of SS release inhibition at high Cae concentration occupying the low-affinity CCK-1R. These cells release more than 60% of their SS content by constitutive secretion, confirmed by cycloheximide and brefeldin inhibiting SS synthesis and intracellular trafficking, respectively.
Both CCKR subtypes occupy RIN-14B cells and initiate SS secretion through constitutive secretion controlled at SS synthesis level. Somatostatin secretion via the CCK-1R occupation mobilizes its high-affinity sites.
本研究评估了胆囊收缩素（CCK）受体占据在控制 RIN-14B 细胞生长抑素（SS）分泌中的作用。
通过免疫荧光法证实 CCK 受体 1 和 2 的存在，并通过酶联免疫吸附试验评估 SS 分泌。
通过免疫荧光，95%的细胞群体由同时表达 CCK-R 两种亚型的 SS 细胞组成，β细胞占 5%（未显示数据）。胆囊收缩素（Cae），CCK-1R 激动剂，和五肽胃泌素，CCK-2R 激动剂，剂量依赖性地增加 SS 释放，1 mumol/L Cae 时增加 3 倍，10 mumol/L 五肽胃泌素时增加 2.5 倍，CCKRs 的占据由 L-364,178 和 L-365,260 对 CCK-1R 和 CCK-2R 的抑制证实。CCae 对高亲和力 CCK-1R 的占据通过 JMV-180 证实，JMV-180 是一种高亲和力 CCK-1R 激动剂，并且在高 Cae 浓度下没有 SS 释放抑制，占据低亲和力 CCK-1R。这些细胞通过组成型分泌释放超过 60%的 SS 含量，这通过环已酰亚胺和布雷非德菌素分别抑制 SS 合成和细胞内运输得到证实。
两种 CCKR 亚型占据 RIN-14B 细胞，并通过在 SS 合成水平上控制的组成型分泌启动 SS 分泌。通过 CCK-1R 占据引发的 SS 分泌会动员其高亲和力位点。
