In situ hybridization analysis of hepatic cytochrome P450 2E1 messenger ribonucleic acid in mice. Modulation of expression by acetone.
BACKGROUND
Cytochrome P450 2E1 is a distinct enzyme induced by diverse agents and notably by solvents including acetone. The P450 2E1 apoprotein is predominantly localized in the centrilobular region of the hepatic lobule in the constitutive state and after induction with acetone. In this study, we investigated the level and pattern of distribution of the 2E1 mRNA within the hepatic lobule in control mice and in mice exposed to acetone under acute and chronic conditions.


METHODS
Male CD-1 mice were administered acetone acutely (5 ml/kg) or chronically (1% in drinking water for 8 days). Cytochrome P450 2E1 mRNA was detected in liver tissues, using in situ hybridization with a 3H-labeled RNA probe coupled with quantitative image analysis.


RESULTS
Acetone exposure did not alter the distance spanning a central vein and an adjacent portal vein. In control mice, 2E1 mRNA transcripts were localized most abundantly in the centrilobular zone of the hepatic lobule; intermediate levels were found in the midzonal region, and minimal levels were found in the periportal region. In acetone-treated mice, 2E1 mRNA expression within the hepatic lobule was significantly reduced and was manifested, firstly, in a decreased hepatocyte population with high expression, as assessed by reduction of total acinar areas containing 2E1 mRNA transcripts, and, secondly, in reduced 2E1 mRNA content within the hepatocytes. These alterations were observed to a significantly greater extent in mice after chronic versus acute acetone exposure.


CONCLUSIONS
Our results showed that acetone exposure in mice results in both a reduction and a more restricted distribution of 2E1 mRNA within the hepatic lobule. Furthermore, these findings suggest that 2E1 enzyme induction is associated with post-transcriptional events that are more marked after chronic than after acute exposure.
Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada.
P G
PG
Forkert
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S
Chen
A C
AC
Jackson
D000096:Acetone / Q000494:pharmacology*; D000818:Animals; D019392:Cytochrome P-450 CYP2E1; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis* / Q000235:genetics; D007091:Image Processing, Computer-Assisted; D017403:In Situ Hybridization; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010089:Oxidoreductases, N-Demethylating / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism
D012333:RNA, Messenger; D000096:Acetone; D003577:Cytochrome P-450 Enzyme System; D019392:Cytochrome P-450 CYP2E1; D010089:Oxidoreductases, N-Demethylating