Marchesini G, Forlani G, Zoli M, Dondi C, Bianchi G, Bua V, Vannini P, Pisi E
Hepatology. 1983 Mar-Apr;3(2):184-7. doi: 10.1002/hep.1840030208.
To test the hypothesis that hyperinsulinism is responsible for reduced branched-chain amino acids in cirrhotics, plasma amino acids were sequentially determined in 8 controls and 8 matched cirrhotics during continuous i.v. insulin infusion. An artificial endocrine pancreas which infused glucose was used to sustain euglycemia. Basal plasma insulin levels were high and branched-chain amino acids were reduced in cirrhotics. Insulin infusion raised insulin levels to 3 to 4 times basal values. During the test, the decline in branched-chain amino acids was markedly higher in controls who had similar steady-state insulin levels. Not only did the level of branched-chain amino acids in controls reach the values seen in cirrhotics after 60 min, but the levels continued to fall at a significantly higher rate throughout the second hour. Glucose consumption and the ratio of glucose infused/steady-state insulin--a measure of tissue sensitivity to insulin--were markedly reduced in cirrhotics and positively correlated with the decline in branched-chain amino acids. In cirrhotics, insulin effects on carbohydrate and branched-chain amino acid metabolism were reduced. Low branched-chain amino acid levels in cirrhotics are not likely to depend only on hyperinsulinism.
为了验证高胰岛素血症是导致肝硬化患者支链氨基酸减少的原因这一假说，在8名对照者和8名匹配的肝硬化患者持续静脉输注胰岛素期间，对其血浆氨基酸进行了连续测定。使用输注葡萄糖的人工内分泌胰腺来维持血糖正常。肝硬化患者的基础血浆胰岛素水平较高，支链氨基酸减少。胰岛素输注使胰岛素水平升高至基础值的3至4倍。在测试过程中，稳态胰岛素水平相似的对照者中支链氨基酸的下降明显更高。对照者的支链氨基酸水平不仅在60分钟后达到了肝硬化患者的水平，而且在第二个小时内继续以明显更高的速度下降。肝硬化患者的葡萄糖消耗量以及输注葡萄糖/稳态胰岛素的比值（衡量组织对胰岛素敏感性的指标）明显降低，且与支链氨基酸的下降呈正相关。在肝硬化患者中，胰岛素对碳水化合物和支链氨基酸代谢的作用减弱。肝硬化患者支链氨基酸水平低不太可能仅取决于高胰岛素血症。
