The Effect Of Glucose And Insulin On Gene Expression Related To Lipids Metabolism And TG Accumulation In Goose Hepatocyte

Disorder of lipids metabolism could induce abnormal fatty deposition,then result in hepatic steatosis in animal hepatocyte,which could be the reason of the change of mRNA expression of genes related to the lipids metabolism in the effect of hormone and nutriment.In this study,with the Landes geese and Sichuan White geese as material,we measured the effect of glucose and insulin on TG accumulation,the gene expression of SREBP-1,FAS,ACCαand LPL,and the enzyme activity of FAS and ACC in hepatocyte. The role of insulin and glucose in hepatic steatosis was discussed,which could establish the ground of the molecular mechanism of hepatocytes steatosis.The results were as follow:1) The hepatocytes activity increased with the increasing of insulin concentration,and 150nmol/L insulin was the optimal concentration of cell growth,while 200 nmol/L insulin would cause insulin resistance and reduced insulin sensitivity of hepatocyte.Glucose could increase the hepatocyte activity,and insulin and glucose had a synergism role on the hepatocyte activity.2) Both insulin and glucose could increase TG content of goose hepatocyte at different extent.In the condition of 50 nmol/L insulin and high glucose(30 mmol/L),TG content reached the maximum;however,TG content in both breeds was decreased by 200nmol/L insulin,and the TG content of Sichuan White goose was only 46.90%of control group.3) The mRNA level in goose hepatocyte was detected.It was found that insulin could increase mRNA level of SREBP-1,FAS,ACCαand the LPL,while glucose only enhanced the gene expression of FAS and LPL,have no or less impact to the other two genes.In addition,when insulin and glucose together cultured,the mRNA level of these genes all increased,particularly SREBP-1,FAS and LPL.4) The data showed that ACC and FAS activity in goose primary hepatocyte treated with insulin and glucose were enhanced,and ACC activity didn't significantly increase in hepatocyte treated with only glucose,but ACC activity significantly increased in the condition of insulin and glucose cultured together(P<0.01).5) By analysising the change of SREBP-1,FAS and ACCαmRNA level,we presumed that SREBP-1 and glucose couldn't regulate the gene expression of ACCα,but insulin can induce ACCαgene transcription.The conclusion is contrary to the previous reports.The induction of insulin to FAS gene can be mediated by SREBP-1,and FAS mRNA expression could be directly controlled by glucose or be mediated by other transcription factors excluding SREBP-1.6) The hepatic steatosis may be closely related to FAS gene transcription and its enzyme activity.7) Gene expression of LPL may play an important role on the use and storage of triglycerides in goose hepatocyte,which may be one reason of hepatic steatosis.