Department of Toxicology, School of Pharmacy, University of London, 29/39 Brunswick Square, WC1N 1AX, London, UK.
Amino Acids. 1996 Jun;10(2):173-85. doi: 10.1007/BF00806590.
The synthesis of taurine fromN-acetylcysteine has been examined in ratsin vivo and in rat hepatocyte suspensionsin vitro. In ratsin vivo, administration ofN-acetylcysteine significantly increased urinary taurine (3 fold) 24h after dosing and liver glutathione levels. Liver taurine was not increased significantly. In hepatocytes incubated in the presence ofN-acetylcysteine, glutathione concentration increased to a maximum after 1 hour but the increase was not dependent on the concentration ofN-acetylcysteine. In contrast, after an initial lag phase, taurine synthesis increased in relation to the concentration ofN-acetylcysteine and continued for 3 hours. Glutathione synthesis seems to be preferential to taurine synthesis. Taurine synthesis from cysteine sulphinate was greater and from hypotaurine was greatest and maximal after 1 hour. Implications for the mechanism of protection byN-acetylcysteine are discussed.
牛磺酸可由 N-乙酰半胱氨酸在体内的大鼠和体外的大鼠肝细胞悬液中合成。在体内的大鼠中，给予 N-乙酰半胱氨酸后 24 小时，尿牛磺酸（增加 3 倍）和肝谷胱甘肽水平显著增加。肝牛磺酸没有明显增加。在存在 N-乙酰半胱氨酸的情况下孵育的肝细胞中，谷胱甘肽浓度在 1 小时后达到最大值，但增加与 N-乙酰半胱氨酸的浓度无关。相比之下，在初始滞后阶段之后，牛磺酸合成与 N-乙酰半胱氨酸的浓度相关增加，并持续 3 小时。谷胱甘肽合成似乎优先于牛磺酸合成。牛磺酸合成来自半胱氨酸亚磺酸盐，来自次牛磺酸的最大和最大在 1 小时后。讨论了 N-乙酰半胱氨酸保护机制的意义。
