高糖对肝脏胰高血糖素受体的表达及作用影响  

Effects of high glucose on the expression and function of glucagon receptor in the liver

作　　者：刘梦丹 冀琳琳 叶阳 祝超瑜[1] 肖元元[1] 高清歌[1] 魏丽[1] LIU Mengdan;JI Linlin;YE Yang;ZHU Chaoyu;XIAO Yuanyuan;GAO Qingge;WEI Li(Department of Endocrinology and Metabolism,the Sixth People′s Hospital Affiliated to Shanghai Jiao Tong University,Shanghai 200233,China)

机构地区：[1]上海交通大学附属第六人民医院内分泌代谢科

出　　处：《中国医药导报》2019年第22期12-16,F0004,共6页China Medical Herald

基　　金：国家自然科学基金资助项目(81570778);上海健康医学院种子基金项目(SFP-18-20-14-001)

摘　　要：目的观察db/db小鼠肝组织和高糖对待的肝癌细胞株HepG2细胞中胰高血糖素受体(GCGR)的表达及作用的变化。方法db/db小鼠和对照小鼠均进行腹腔注射葡萄糖耐量试验(IPGTT)和腹腔注射胰岛素耐量试验(IPITT),收集两组小鼠的血液进行生化指标检测;采用Westernblot或免疫组化法检测两组小鼠肝脏中GCGR、蛋白激酶A(PKA)、磷酸化蛋白激酶A(p-PKA)的表达情况。采用Westernblot法检测在无胰高血糖素(GLN)刺激下,不同糖浓度或不同时间梯度高糖(30mmol/L)处理的HepG2细胞GCGR的表达情况,以及在GLN刺激下,不同时间梯度高糖处理的HepG2细胞GCGR、PKA、p-PKA蛋白的表达情况。结果与对照小鼠比较,db/db小鼠肝脏GCGR表达增加,而PKA磷酸化水平下降(P<0.05或P<0.01)。HepG2细胞的GCGR蛋白表达水平随葡萄糖浓度增加而升高,随高糖作用时间延长先下降后升高(均P<0.01)。GLN刺激下,随着高糖对待时间的增加,GCGR蛋白表达水平逐渐升高(均P<0.01);p-PKA/PKA水平则较对照组(0h)降低(P<0.05或P<0.01)。结论慢性高糖可增加肝脏GCGR的表达,并导致肝脏胰高血糖素抵抗。Objective To investigate the changes of the expression and function of glucagon receptor (GCGR) in db/db mice liver and hepatocellular carcinoma cell line HepG2 cells treated with high glucose.Methods Intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tolerance test (IPITT) were performed in both db/db mice and control mice.The blood of mice in the two groups was collected for biochemical test;the expression of GCGR,protein kinase A (PKA) and phosphorylated protein kinase A (p-PKA) in the liver of the two groups were detected by Western blot or immunohistochemistry.The expression of GCGR in HepG2 cells treated with high glucose (30 mmol/L) in different glucose concentrations or different time gradients was detected by Western blot without stimulation of glucagon (GLN).Under GLN stimulation,the expression of GCGR,PKA and p-PKA proteins in HepG2 cells treated with high glucose at different time gradients was also detected by Western blot.Results Compared with control mice,the expressions of GCGR were markedly elevated in liver of db/db mice,but phosphorylated PKA levels were decreased (P < 0.05 or P < 0.01).GCGR protein expressions were increased following the growth of glucose concentrations in HepG2 cells,meanwhile,the expressions of GCGR protein were decreased at first,then increased with time extended (all P < 0.01).Under GLN stimulation,the GCGR protein levels were upregulated by high glucose in a time-dependent manner (P < 0.01).However,p-PKA/PKA levels were decreased compared with control group (0 h)(P < 0.05 or P < 0.01).Conclusion Chronic hyperglycemia can increase the expression of GCGR in the liver and lead to glucagon resistance in the liver.

关 键 词：胰高血糖素受体 胰高血糖素抵抗 糖尿病 DB/DB小鼠 HEPG2细胞 

分 类 号：R587[医药卫生—内分泌]