Spot 14基因研究进展

甲状腺激素应答蛋白基因spot 14已被证实在脂肪合成过程中有着重要的作用，主要表现在对ATP柠檬酸酶、脂肪酸合成酶和苹果酸酶等脂肪合成酶基因表达的调控作用。简要综述了Spot 14基因在动物脂肪合成方面的最新研究进展，并提示对spot 14基因的深入研究将有助于阐明机体脂肪沉积的规律．     

Toll样受体4对饥饿代谢的调控作用

Toll样受体4( Toll-like receptor 4,TLR4)的激活能介导炎症反应.对于高脂饲料喂养导致的肥胖小鼠,TLR4激活所引起的炎症反应是引起胰岛素抵抗和代谢紊乱的重要原因.虽然已知TLR4参与病理性代谢反应,但它在生理状态下对代谢是否具有调控作用尚不清楚.我们将TLR4基因敲除(TLR4~-/-)小...     

Tannic acid inhibits insulin-stimulated lipogenesis in rat adipose tissue and insulin receptor function in vitro

Tannins occur naturally in relatively abundant amounts in fruits, herbal medicines and common beverages. Thus an understanding of how these polyphenols affect peptide hormone action is of importance. We report here that tannic acid (a hydrolysable tannin) inhibits insulin-stimulated lipogenesis in rat adipose tissue in vitro, with an IC₅₀ estimated to be about 350 M. However, its monomer, gallic acid, did not show a similar inhibitory effect at concentrations up to 1 mM. The inhibition by tannic acid was less evident with higher concentrations of bovine serum albumin in the incubation buffer. This was attributed to the formation of a tannin-protein complex between bovine serum albumin and tannic acid. In a binding assay, it was observed that the specific binding of insulin to its receptor was not inhibited by tannic acid in the concentration range 0–200 M. However, insulin-stimulated autophosphorylation of the insulin receptor, and receptor-associated tyrosine kinase phosphorylation of RR-SRC peptide, were inhibited by tannic acid at concentrations as low as 25 M. Our data do not support the current speculation that tannins affect the activity of peptide hormones by binding to them. Therefore, our finding opens up a new perspective in the understanding of the mode of action of tannins on such hormones.