ALTERNATIVE REGULATION BETWEEN THE Ya AND Yc SUBUNIT OF LIVER GLUTATHIONE S-TRANSFERASES IN HEPATITIS AND CANCEROUS RATS

大鼠自发性肝炎在某些方面与人类急性肝炎和肝癌相似。大鼠肝炎发生于4月龄左右，严重黄疸的大鼠多在1周内死亡。已知肝炎被鉴定为孟德尔型隐性突变。我们推测大鼠肝炎的机制可能是由于肝脏酶的改变或缺乏。最近。我们证实，繁殖一年以上的大鼠有肝脏肿瘤。众所周知，谷胱甘肽s -转移酶是肝脏的主要代谢酶，也是肝癌的良好标志物。-即该酶的表达反映了肝脏的情况。采用-s-己基谷胱甘肽连接琼脂糖柱，色谱聚焦法，从肝炎大鼠和正常大鼠体内纯化谷胱甘肽s-转移酶，探讨肝炎和肝癌发生的机制。分离出7种主要的谷胱甘肽s-转移酶。我们发现谷胱甘肽s -转移酶1-1显著降低，相反谷胱甘肽s -转移酶2-2显著升高。众所周知，这些基因非常相似，但又不同。因此，该基因在肝炎大鼠肝脏中的表达似乎发生了改变。谷胱甘肽s -转移酶4-4也增加。我们制备了谷胱甘肽s -转移酶2-2和兔抗谷胱甘肽s -转移酶4-4特异性单克隆抗体。采用免疫组化方法对有肿瘤结节的肝脏切片进行酶定位。谷胱甘肽s -转移酶2-2和4-4的表达似乎不在肿瘤结节内。与正常大鼠相比，肝炎大鼠的基因表达明显改变。目前尚不清楚这种改变是由于临床现象还是遗传因素。基因分析正在进行中。

Spontaneously hepatitis in rats are similar in certain respects to human acute hepatitis and liver cancer. The hepatitis in rats occur at the age of approximately 4 months old and most rats with severe jaundice were died within one week. It was known that the hepatitis was identified as a recessive mutation of mendelian fashion. We have postulated that the mechanism of the hepatitis in rat may be due to enzyme alterations or lack in the liver. Recently. we confirmed that the rats which were breeding for over one year had liver tumors. It is well known that glutathione S-transferases are major metabolic enzyme in liver and very good marker of hepatoma.-Namely, expression of this enzyme reflects circumstances of liver.In order to investigate the mechanism of hepatitis and then hepatoma, glutathione S-transferases were purified from hepatitis rats and normal rats by -s-hexylglutathione-linked agarose column, chromatofocusing. Seven major glutathione s-transferases were isolated. We found that glutathione S-transferase 1-1 was markedly decrease, and conversely glutathione S-transferase 2-2 was markedly increase. It is known that the genes are very similar but different genes. So it seems that the gene expression alters in hepatitis rat liver. Glutathione S-transferase 4-4 also increased.We have produced a monoclonal antibody specific for glutathione S-transferase 2-2 and rabbit anti glutathione S-transferase 4-4. We determined the enzyme localization on the liver section which had neoplastic nodules by immunohistochemical method using the antibodies. The expression of glutathione S-transferase 2-2 and 4-4 seemed to be out of the neoplastic nodules.It is obvious that the gene expression alters in hepatitis rats as compared with in normal rats. It is not clear whether such a alteration is due to a clinical phenomenon, or genetical factor. Genetic analysis is now in progress.