[An immunohistochemical and in situ hybridization study of carbamyl phosphate synthetase I in altered liver cells during carcinogenesis].

In order to study the changes of phenotype and gene expression of carbamyl phosphate synthetase I (CPS 1) in preneoplastic altered liver cells in situ, serial cryostat sections of rat liver initiated by diethylnitrosamine (DENO) and promoted by phenobarbital (PB) were hybridized with 35S-GPS 1 cDNA probe by in situ hybridization, and immunohistochemical demonstration (PAP) of CPS 1 were made simultaneously. The results showed that abnormal expression of CPS 1 in the altered foci and nodules increased much more rapidly than that in normal ones, and consequently they might be more susceptable to develop into tumor.