Rossi M A, Dianzani M U
Dipartimento di Medicina ed Oncologia Sperimentale, Università degli Studi di Torino, Italia.
Tumori. 1988 Dec 31;74(6):617-21. doi: 10.1177/030089168807400601.
The importance of some glutathione metabolic pathways was examined in two highly dedifferentiated hepatomas, Yoshida AH-130 and Morris 3924 A hepatomas, and in normal liver in relation to their role against oxidative stress. The cytosol prepared from Yoshida hepatoma cells decreased the peroxidation rate in normal liver microsomes and mitochondria, but this antioxidant property was not displayed by Morris hepatoma. Glutathione peroxidase and glutathione-S-transferases activities were extremely low in both hepatomas; glutathione reductase activity values were about half the normal liver values. The large decrease in glutathione peroxidase and glutathione-S-transferases suggests that in these two tumors only small amounts of GSH can be used in reduction or conjugation reactions, such as the reduction of hydrogen peroxide and lipid hydroperoxides or the conjugation of GSH with the end products of lipoperoxidation, aldehydes or ketones. The hypothesis of a more efficient GSSG reduction in hepatomas, due to the low glutathione peroxidase/glutathione reductase activity ratio, is also discussed. The described changes in glutathione related enzymes do not seem to have any correlation with the protective effect against the lipoperoxidative processes displayed by some tumors since these enzymatic activities were similar in both hepatomas whereas only Yoshida hepatoma showed antioxidant properties.
研究了吉田AH - 130和莫里斯3924 A肝癌这两种高度去分化的肝癌以及正常肝脏中某些谷胱甘肽代谢途径的重要性，及其在抵抗氧化应激方面的作用。吉田肝癌细胞制备的胞质溶胶降低了正常肝脏微粒体和线粒体中的过氧化速率，但莫里斯肝癌不具有这种抗氧化特性。两种肝癌中的谷胱甘肽过氧化物酶和谷胱甘肽 - S - 转移酶活性极低；谷胱甘肽还原酶活性值约为正常肝脏值的一半。谷胱甘肽过氧化物酶和谷胱甘肽 - S - 转移酶的大幅降低表明，在这两种肿瘤中，只有少量的谷胱甘肽可用于还原或结合反应，如过氧化氢和脂质氢过氧化物的还原，或谷胱甘肽与脂质过氧化终产物醛或酮的结合。还讨论了由于谷胱甘肽过氧化物酶/谷胱甘肽还原酶活性比低，肝癌中谷胱甘肽二硫化物还原效率更高的假说。谷胱甘肽相关酶的上述变化似乎与某些肿瘤对脂质过氧化过程的保护作用没有任何关联，因为这两种肝癌中的这些酶活性相似，而只有吉田肝癌表现出抗氧化特性。
