Suzuki H, Mamata Y, Mizuno H, Tominaga T, Suga M, Suemori S, Sato A, Suzuki M
Department of Internal Medicine, Yokohama City Seibu Hospital, St. Marianna University School of Medicine, Yokohama, Japan.
Alcohol Clin Exp Res. 1998 May;22(S3 Pt 1):137S-140S. doi: 10.1111/acer.1998.22.s3_part1.137s.
We investigated whether the reduction of plasma tyrosine in alcoholic liver disease would affect the branched-chain amino acid/tyrosine molar ratio (BTR) measured using an enzymatic assay method in alcoholic cirrhosis. BTR values were higher in patients with compensated and decompensated alcoholic cirrhosis (5.68 +/- 2.29 and 3.28 +/- 0.75) due to reduction of the tyrosine level relative to those in patients with nonalcoholic cirrhosis (3.64 +/- 1.22 and 2.53 +/- 0.99). A decrease in tyrosine level and an increase in BTR value were observed after single ethanol administration to healthy subjects. As significant elevation of serum immunoreactive insulin levels followed elevation of serum glucose levels after alcohol loading, it was thought that insulin accelerated intrahepatic metabolism of aromatic amino acids, resulting in reduction of the tyrosine level. The same mechanism may be applied to tyrosine reduction in patients with alcoholic cirrhosis during heavy drinking.
我们研究了酒精性肝病患者血浆酪氨酸水平的降低是否会影响采用酶法测定的酒精性肝硬化患者的支链氨基酸/酪氨酸摩尔比（BTR）。由于酪氨酸水平相对于非酒精性肝硬化患者降低，代偿期和失代偿期酒精性肝硬化患者的BTR值更高（分别为5.68±2.29和3.28±0.75），而非酒精性肝硬化患者的BTR值分别为3.64±1.22和2.53±0.99。对健康受试者单次给予乙醇后，观察到酪氨酸水平降低和BTR值升高。由于饮酒后血清葡萄糖水平升高后血清免疫反应性胰岛素水平显著升高，推测胰岛素加速了芳香族氨基酸的肝内代谢，导致酪氨酸水平降低。相同的机制可能适用于重度饮酒期间酒精性肝硬化患者的酪氨酸降低情况。
