12 research outputs found
Expression of Cytochrome P-450 and Albumin Genes in Rat Liver: Effect of Xenobioticst
Thioacetamide, a hepatocarcinogen and an inhibitor of heme synthesis, blocks the phenobarbitone-
mediated increase in the transcription of cytochrome P-450b+e messenger RNA in rat liver. This
property is also shared by CoCl, and 3-amino-l,2,4-triazole, two other inhibitors of heme synthesis. Thus,
it appears feasible that heme may serve as a positive regulator of cytochrome P-450b+e gene transcription.
Thioacetamide enhances albumin messenger RNA concentration, whereas phenobarbitone decreases the
same. However, these changes in albumin messenger RNA concentration are not accompanied by corresponding
changes in the transcription rates. Therefore, drug-mediated changes in albumin messenger RNA
concentration are due to posttranscriptional regulation. The property of thioacetamide to enhance the albumin
messenger RNA concentration is not shared by CoC1, and 3-amino- 1,2,4-triazole. Therefore, heme does
not appear to be a regulatory molecule mediating the reciprocal changes brought about in the concentrations
of cytochrome P-450b+e and albumin messenger RNAs