مستخلص: |
The expression and regulation of the phosphoenolpyruvate carboxykinase gene were not grossly modified by feeding rats a 3'‐methyl‐4‐(dimethylamino)azobenzene‐containing diet despite maximum expression of the L‐type pyruvate kinase gene being dramatically reduced as early as the 24th hour of the carcinogenic diet. Inhibition of aldolase B mRNA synthesis occurred more slowly, being maximum at the 3rd day. After stopping administration of the carcinogen, a very rapid, but transient increase of the L‐type pyruvate kinase mRNA was observed at the 24th hour, whereas aldolase B mRNA increased only slowly. The amount of aldolase A mRNA fell quickly after termination of carcinogen administration, levels being normal at the 2nd–3rd day. At this time, the histological structure of the liver was indistinguishable from that of animals still receiving the azo‐dye diet. It appears, therefore, that in the rat both administration and withdrawal of the azo‐dye carcinogen induce rapid modifications of the expression of some genes, before any cellular modification is distinguishable. |