1. [Modulation of mRNAs P450 and hepatocarcinogenesis promotion].
- Author
-
Lechner MC, Ribeiro VL, Henrique D, Barroso M, and Cravino MM
- Subjects
- Animals, Enzyme Induction drug effects, Liver Neoplasms, Experimental chemically induced, Phenotype, Rats, Carcinogens pharmacology, Cytochrome P-450 Enzyme System biosynthesis, Liver drug effects, Phenobarbital pharmacology, RNA, Messenger drug effects
- Abstract
The adaptive response of the liver to phenobarbital is characterized by a strong cell hypertrophy and coordinate induction of specific P450 forms (IIB1, 2; IIC7, IIIA1). The pattern of active mRNA is significantly changed, demonstrating the establishment of PB phenotype. Employed as a promoting agent in experimental hepatocarcinogenesis, PB triggers a significantly different, uncoordinated response. Only P450 IIB1 is positively modulated while P450 IIC7 mRNA becomes repressed. Mechanisms underlying the differential P450 adaptative response to PB in the initiated versus non-initiated liver are discussed in the light of both the importance of epigenetic events and the possible role of P450 mono-oxygenases in hepatocarcinogenic promotion by PB.
- Published
- 1990