科研之友
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摘要
Apelin is a peptide known as the ligand of the G protein-coupled receptor APJ. Diverse active apelin peptides exist in the form of 13, 17 or 36 amino-acids originating from a 77-amino-acid precursor. Apelin and APJ are expressed in the central nervous system, particularly in the hypothalamus, and in peripheral tissues such as heart, adipose tissue, the endothelial cells of blood vessels and skeletal muscle. Apelin has been shown to be involved in the regulation of fluid homeostasis, food intake, cell proliferation and vessel formation. Apelin is also an important regulator of cardiovascular homeostasis by stimulating NO-dependent vasodilatation and increasing cardiac contractility. Down-regulation of apelin and APJ expression is associated with decreased cardiac performance but exogenous apelin restores it raising the possibility of investigating its therapeutic potential. Recently, apelin effects on energy metabolism have been demonstrated. Results obtained in our laboratory have shown that in vivo, in mice, intravenous injection of apelin decreases blood glucose and increases glucose utilization in skeletal muscle and adipose tissue. Activation of glucose transport by apelin in muscle implies a pathway partially independent of insulin signalling, involving the activation of AMP-activated protein- kinase and of endothelial NO-synthase. In obese and insulin-resistant mice, an intravenous injection of apelin improves glucose tolerance and stimulates the entry of glucose into insulin-sensitive tissues. Thus, apelin (acute treatment) regulates glucose homeostasis and is effective in insulin-resistant mice. The heart is also an important site of active metabolism and metabolic alterations are observed during diabetes. Since the apelin/APJ system is highly expressed in the heart, the effects of apelin on cardiac energy metabolism opens new interesting prospects.
- 出版日期2009-9
- 单位河北医科大学
