Administration of 3-methylcholanthrene to rats increases the specific hybridizable mRNA coding for cytochrome P-450c.
Poly(A)+-RNA obtained from the livers of 3-methylcholanthrene (3MC)-treated rats was translated into cytochrome P-450c in a cell-free reticulocyte system. In this translational system, no precursor cytochrome P-450c was observed. The mRNA responsible for the synthesis of this cytochrome was isolated by immunoprecipitation of liver polyribosomes obtained at 15 hr after 3MC treatment, and a cDNA was constructed by the reverse transcriptase reaction. The cDNA was further purified by hybridizing at a high R0t (product of RNA concentration and incubation time) to poly(A)+-RNA isolated from control rat liver, and the nonhybridized, single-stranded cDNA was isolated by hydroxylapatite chromatography. This cDNAp-450c was employed in hybridization reactions with poly(A)+-RNA isolated from the livers of rats treated with 3MC for various times. These studies indicated a maximal induction of mRNAp-450c at about 15 hr after 3MC injection, although levels of this mRNA were significantly increased by 7 hr. The mRNAp-450c concentration had diminished by 24 hr but remained higher than control levels for at least 48 hr. These studies establish an effect of 3MC upon the accumulation of mRNAp-450c in rat liver.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000235:genetics*; D004790:Enzyme Induction / Q000187:drug effects; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology*; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
D012333:RNA, Messenger; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System