Properties of the increased glutathione S-transferase a form in rat preneoplastic hepatic lesions induced by chemical carcinogens

Regulation of glutathione transferase and DT-diaphorase mRNAs in persistent hepatocyte nodules during chemical hepatocarcinogenesis.

“…3B and Table 4). There was very little difference between the level The increase in the various mRNA levels observed in this study is consistent with the increases found in the catalytic activity and/or level of glutathione transferases and DT-diaphorase in persistent hepatocyte nodules by other investigators (6,10,11). Consequently it would appear that the synthesis of these enzymes are increased specifically in the nodules as compared to the surrounding liver tissue and suggest a differential expression of the glutathione transferase and DT-diaphorase genes in nodular versus surrounding liver tissue during chemically induced neoplastic transformation.…”

“…Persistent hepatocyte nodules are thought to represent precursors for the subsequent development of hepatocellular carcinomas and, thus, have been utilized as a model system to study chemically induced neoplastic transformation (1,2). Biochemically the nodules have elevated levels of various drug-metabolizing enzymes {e.g., glutathione transferases (glutathione S-aralkyltransferase; RX:glutathione R-transferase, EC 2.5.1.18), DT-diaphorase [NAD(P)H:quinone-acceptor oxidoreductase, EC 1.6.99.2], and epoxide hydrolase}; however, cytochrome P-450 levels appear to be depressed (3)(4)(5)(6)(7)(8)(9)(10)(11). The elevated levels of some phase II drugmetabolizing enzyme activities and a decreased level of cytochrome P-450 are consistent with the observation that persistent hepatocyte nodules are more resistant to the cytotoxic effects of carcinogens as compared to normal liver (12).…”

Glutathione and related enzyme activity in human lung cancer cell lines

“…However, it is known that these proteins exhibit variable substrate specificity (Mannervik, 1985) and are representative of a multigene family. An acidic transferase has been implicated in the resistance associated with preneoplasia (Kitahara & Satoh, 1983;Faber, 1984) and in MCF 7 cells in vitro, that express the multidrug resistance phenotype (Batist et al, 1986). In an attempt to identify a resistance 'marker' for lung cancer, it is intended to extend these studies to include an analysis of the GST isoenzyme pattern of these cell lines.…”

Chemical Carcinogenesis: The Liver as a Model

“…In addition, the nodules from different models show a special poly peptide with a molecular weight of 26 kilodaltons in the cytosol. This has recently been identified as being the same as the placental glutathione-S-transferase of Sato and his colleagues [85][86][87][88].…”