癌变过程中肝总RNA和嘌呤代谢酶的表达与动态改变

目的　观察腺苷脱氨酶（ａｄｅｎｏｓｉｎｅ ｄｅａｍｉｎａｓｅ，ＡＤＡ） 和鸟嘌呤酶（ｇｕａｎａｓｅ， ＧＵＡ） 在肝细胞癌变过程中的表达与动态变化。方法　以２乙酰氨基芴（２ＦＡＡ） 喂饲大鼠诱发肝癌，在肝细胞癌变过程中，对肝组织学、总ＲＮＡ 浓度、ＧＵＡ 和ＡＤＡ 活性的动态改变进行了分析。结果　大鼠摄入２ＦＡＡ后，ＧＵＡ和ＡＤＡ的活性均迅速升高，并与总ＲＮＡ浓度呈正相关。在肝细胞变性至癌前病变阶段，肝和血ＡＤＡ明显升高（ Ｐ＜０ ．０１） ，而后血ＡＤＡ 迅速降至正常；血ＧＵＡ 在肝细胞癌变过程中酶活性持续升高，并与肝ＧＵＡ相一致，鼠肝完全癌变时酶活性达高峰。结论　ＡＤＡ 在肝细胞损伤早期比ＡＬＴ 和ＧＳＴ敏感，ＧＵＡ活性持续升高则表示肝病程度严重。

Expression and kinetic alterations of hepatic total RNA concentration and purine metabolic enzymes during the development of rat hepatomas

Objective To observe the expression and kinetic alteration of adenosine deaminase (ADA) and guanase (GUA) during the carcinogensis of rat livers. Methods The rat hepatic histologic changes, total RNA Levels, GUA and ADA activities were observed in experimental rat hepatomas induced by 2 FAA. Results The GUA and ADA activities increased rapidly in the rats fed with 2 FAA, and positive correlations were found between GUA or ADA activity and total RNA concentration. The activities of liver and serum ADA were overexpressed and significantly higher ( P <0.01) in experimental rats from hepatocyte degeneration to precancerous stage, then serum ADA activity decreased to normal level; The increases of serum GUA levels were consonant with hepatic GUA concentrations, and the marked expressions of serum GUA and liver GUA occurred at hepatoma stage of experimental rats. Conclusions The present data suggest that ADA is a more sensitive marker than ALT or GST in the early stage of hepatocellular injury, and everlasting increase of GUA implicates serious damage of hepatocytes.