Regulation Of AMP-activated Protein Kinase On Cholesterol Metabolism Of Laying Hens

In order to realize the regulation of lipid metabolism of laying hens and reduction of cholesterol content in eggs, the mechanism on cholesterol metabolism of laying hens and cholesterol deposition must be known. AMP-activated protein kinase (AMPK ) is recognized as a major regulator of lipid biosynthetic pathway due to its role in the phosphorylation and inactivation of key enzymes such as acetyl-CoA carboxylase (ACC) and β-hydroxy-β-methylglutary-CoA reductase (HMGR) , as a result, triglyceride and cholesterol biosyntheses being inhibited. Cholesterol biosynthesis takes place primarily in the liver of laying hens. It was suggested that AMPK might be involved in cholesterol metabolism of laying hens. Based on an AMPK activation model in the live laying hens, this research was to study whether AMPK regulates lipid metabolism of laying hens. Four experiments were conducted to determine whether AMPK might regulate lipid metabolism and cholesterol deposition of laying hens and to further study the relationship between AMPK and lipid metabolism in laying hens.Experiment 1 was to find activator of AMPK in hepatocytes of laying hens. AMPK was activated in response to 5-amino-imidazolecarboxamide riboside(AICAR) in primary cultured hepatocytes of laying hens . The effects of metformin on AMPK activity and its downstream effector, ACC HMGR activity in primary cultured hepatocytes of laying hens were studied. Four treatments were employed in this experiment. 0.5mmol/L AICAR, 0.5mmol/L metformin, or 1mmol/L metformin were added respectively into the standard culture medium(control). After 100 min incubation, AMPK activity of the 0.5mmol/L and lmmol/L metformin increased by 37.4(P<0.05), 99.2% (P<0.01) respectively,as compared to the control. AMPK inactivated ACC and HMGR which are the major...