| 摘要: |
| 目的 探讨胃饥饿素（ghrelin）能否通过调控环磷酸腺苷/蛋白激酶A （cAMP/PKA）通路竞争性抑制胰高血糖素样肽1（GLP-1）的促胰岛素分泌效应。方法 取8~10周龄雄性SD大鼠5只，分离、纯化大鼠胰岛，经双硫腙（DTZ）和吖啶橙/碘化丙啶（AO/PI）染色鉴定后，每只大鼠挑选60个胰岛，将其随机分成6组并接受不同处理：S0组（8.3 mmol/L葡萄糖溶液）、S1组（8.3 mmol/L葡萄糖溶液+10 nmol/L GLP-1）、S2组（8.3 mmol/L葡萄糖溶液+10 nmol/L GLP-1+10 nmol/L ghrelin）、S3组[8.3 mmol/L葡萄糖溶液+10 nmol/L GLP-1+10 nmol/L ghrelin+1 μmol/L 生长激素促泌素受体1α（GHSR-1α）拮抗剂生长激素释放肽6（D-Lys3-GHRP-6）]、S4组（8.3 mmol/L葡萄糖溶液+10 nmol/L GLP-1+10 nmol/L ghrelin+5 μmol/L腺苷酸环化酶激动剂毛喉素）、S5组（8.3 mmol/L葡萄糖溶液+10 nmol/L GLP-1+10 nmol/L ghrelin+10 μmol/L PKA激动剂6-Phe-cAMP）；所有试剂均于前一试剂处理10 min 后依次加入后一试剂共同处理，每组胰岛的所有处理时间共3 h。采用ELISA法检测各组胰岛培养液中胰岛素和cAMP的浓度。结果 S1组胰岛细胞分泌胰岛素和释放cAMP的浓度均高于S0组（P均<0.05），S2组均低于S1组（P均<0.05）。S3、S4和S5组胰岛细胞分泌胰岛素和释放cAMP的浓度均高于S2组（P均<0.05）。结论 Ghrelin能够抑制GLP-1的促胰岛素分泌效应，其作用机制可能是通过cAMP/PKA通路竞争性抑制GLP-1的促分泌效应。 |
| 关键词: 胃饥饿素 胰高血糖素样肽1 环磷酸腺苷 胰岛素 胰岛 |
| DOI：10.16781/j.0258-879x.2017.05.0679 |
| 投稿时间：2017-02-26修订日期：2017-03-07 |
| 基金项目:国家自然科学基金（81270969，81370984），上海市自然科学基金（12ZR1439100）. |
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| Effect of ghrelin on function of glucagon-like peptide 1 stimulating secretion of insulin through cAMP/PKA pathway |
| WANG Yi-fan,WANG Qiang,ZHANG Wei,QIU Ming* |
(Department of General Surgery(Ⅲ), Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
*Corresponding author) |
| Abstract: |
| Objective To explore whether ghrelin can competitively inhibit glucagon-like peptide 1 (GLP-1) to stimulate the secretion of insulin via cyclic adenosinc monophosphate/protein kinase A (cAMP/PKA) pathway. Methods The pancreatic islets were isolated and purified from five 8-10 weeks old male SD rats, and identified by dithizone (DTZ) and acridine orange (AO)/propidium iodide (PI) staining. Sixty pancreatic islets were selected from each rat and then randomly divided into six groups for different disposals:S0 group (8.3 mmol/L glucose solution), S1 group (8.3 mmol/L glucose solution+10 nmol/L GLP-1), S2 group (8.3 mmol/L glucose solution+10 nmol/L GLP-1+10 nmol/L ghrelin), S3 group (8.3 mmol/L glucose solution+10 nmol/L GLP-1+10 nmol/L ghrelin+1 μmol/L growth hormone-releasing peptide 6[D-Lys3-GHRP-6], an antagonist of growth hormone secretagogue receptor 1α[GHSR-1α]), S4 group (8.3 mmol/L glucose solution + 10 nmol/L GLP-1+10 nmol/L ghrelin+5 μmol/L forskolin, an adenylate cyclase activator), and S5 group (8.3 mmol/L glucose solution + 10 nmol/L GLP-1+10 nmol/L ghrelin + 10 μmol/L 6-Phe-cAMP, a PKA activator); all reagents were added after last reagent treatment for 10 min. Each group had a disposal of three hours totally. ELISA assay was used to detect the concentrations of insulin and cAMP. Results The concentrations of insulin and cAMP in S1 group were significantly higher than those in S0 group (all P<0.05); their concentrations in S2 group were significantly lower than those in S1 group (both P<0.05). The concentrations of insulin and cAMP in S3, S4, and S5 groups were significantly higher than those in S2 group (all P<0.05). Conclusion Ghrelin can inhibit the effect of GLP-1 in promoting secretion of insulin, which may be mediated by cAMP/PKA pathway. |
| Key words: ghrelin glucagon-like peptide 1 cyclic AMP insulin islets of Langerhans |
