Siegers C P, Riemann D, Thies E, Younes M
Institute of Toxicology, Medical University of Lübeck, F.R.G.
Cancer Lett. 1988 May;40(1):71-6. doi: 10.1016/0304-3835(88)90263-7.
The mucosal glutathione content of the gastrointestinal wall amounted to 50-60% of its concentration in the liver. GSH S-aryltransferase activity (CDNB) was very low in the glandular stomach, colon and rectum amounting to only 5% of liver enzyme activity. There was a marked postpyloric increase in GSH S-aryltransferase activity with an oral-aboral decline along the small intestine. GSH peroxidase was much lower in the mucosa of the small and large intestine as compared to the stomach or liver, whereas GSSG reductase was more than twice as high in the gastrointestinal mucosa as compared to the liver showing a gradual increase in activity from proximal to distal segments. The low GSH S-transferase activities found in the stomach, colon and rectum may account for the high and exclusive susceptibility of these segments to carcinogenesis and the deficient inducibility of these enzymes in the gastrointestinal wall may reflect an insufficient adaption towards higher exposure to toxic or even carcinogenic xenobiotics.
胃肠道壁的黏膜谷胱甘肽含量相当于其在肝脏中浓度的50 - 60%。腺胃、结肠和直肠中的谷胱甘肽S - 芳基转移酶活性（CDNB）非常低，仅为肝脏酶活性的5%。幽门后谷胱甘肽S - 芳基转移酶活性显著增加，沿小肠向口 - 肛方向下降。与胃或肝脏相比，小肠和大肠黏膜中的谷胱甘肽过氧化物酶要低得多，而谷胱甘肽二硫化物还原酶在胃肠道黏膜中的活性是肝脏中的两倍多，从近端到远端节段活性逐渐增加。在胃、结肠和直肠中发现的低谷胱甘肽S - 转移酶活性可能解释了这些节段对致癌作用的高度和独特易感性，而这些酶在胃肠道壁中的诱导不足可能反映了对更高水平的有毒甚至致癌性异源生物暴露的适应不足。
