Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

CANCER BIOLOGY: Expression of growth factors and growth factor receptors in the liver of C57BL/10J mice following administration of phenobarbitone

CANCER BIOLOGY: Expression of growth factors and growth factor receptors in the liver of... Liver enlargement is a common feature of non-genotoxic rodent hepatocarcinogens administered at high doses. In the present study, the expression of growth factors and growth factor receptors was investigated in the C57BL/10J mouse during liver enlargement induced by the non-genotoxic rodent hepatocarcinogen, sodium phenobar-bitone (PB). Male mice were dosed 0–2500 p.p.m. PB in the diet for 1, 4 and 13 weeks. There was a dose and time dependent increase in liver weight Hepatocyte replication, assessed by incorporation of bromodeoxyuridine, was increased in a dose-dependent manner at week 1 only (18-fold increase at 2000 p.p.m.) and was predominantly localized in the centrilobular region. At week 1, PB (2500 p.p.m.) caused transient increases in transforming growth factor α (TGFα) and epidermal growth factor receptor (EGFR) and decreases in transforming growth factor β1 (TGF-β1) and mannose-6-phosphate receptor (M6PR) in centrilobular hepatocytes which correlated with the replication in this region. At week 1, there was an increase in both hepatocyte growth factor (HGF) and hepatocyte growth factor receptor (HGFR) which colocalized in centrilobular hepatocytes in some mice or periportal hepatocytes in other mice. After 13 weeks, HGF and HGFR were localized in the cytoplasm of centrilobular hepatocytes of all mice but exhibited a differential intracellular distribution across the lobule. At 2500 p.p.m. PB, EGFR and HGFR mRNA were essentially unchanged over the 13 week dosing period whilst M6PR mRNA was increased 2- to 4-fold. At 2500 p.p.m. PB, EGFR protein levels from immunoblots showed a consistent decrease over the 13 weeks whilst M6PR and HGFR protein levels were essentially unchanged. The protein level and mRNA data for EGFR suggest post-transcriptional modification. Thus, phenobar-bitone caused transient replication of hepatocytes and modulation of growth stimulatory and inhibitory factors and their associated receptors in terms of overall levels and regional distribution in the liver. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Carcinogenesis Oxford University Press

CANCER BIOLOGY: Expression of growth factors and growth factor receptors in the liver of C57BL/10J mice following administration of phenobarbitone

Loading next page...
 
/lp/oxford-university-press/cancer-biology-expression-of-growth-factors-and-growth-factor-jwdHHWyO7P

References (0)

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
Oxford University Press
Copyright
© Oxford University Press
ISSN
0143-3334
eISSN
1460-2180
DOI
10.1093/carcin/17.5.973
Publisher site
See Article on Publisher Site

Abstract

Liver enlargement is a common feature of non-genotoxic rodent hepatocarcinogens administered at high doses. In the present study, the expression of growth factors and growth factor receptors was investigated in the C57BL/10J mouse during liver enlargement induced by the non-genotoxic rodent hepatocarcinogen, sodium phenobar-bitone (PB). Male mice were dosed 0–2500 p.p.m. PB in the diet for 1, 4 and 13 weeks. There was a dose and time dependent increase in liver weight Hepatocyte replication, assessed by incorporation of bromodeoxyuridine, was increased in a dose-dependent manner at week 1 only (18-fold increase at 2000 p.p.m.) and was predominantly localized in the centrilobular region. At week 1, PB (2500 p.p.m.) caused transient increases in transforming growth factor α (TGFα) and epidermal growth factor receptor (EGFR) and decreases in transforming growth factor β1 (TGF-β1) and mannose-6-phosphate receptor (M6PR) in centrilobular hepatocytes which correlated with the replication in this region. At week 1, there was an increase in both hepatocyte growth factor (HGF) and hepatocyte growth factor receptor (HGFR) which colocalized in centrilobular hepatocytes in some mice or periportal hepatocytes in other mice. After 13 weeks, HGF and HGFR were localized in the cytoplasm of centrilobular hepatocytes of all mice but exhibited a differential intracellular distribution across the lobule. At 2500 p.p.m. PB, EGFR and HGFR mRNA were essentially unchanged over the 13 week dosing period whilst M6PR mRNA was increased 2- to 4-fold. At 2500 p.p.m. PB, EGFR protein levels from immunoblots showed a consistent decrease over the 13 weeks whilst M6PR and HGFR protein levels were essentially unchanged. The protein level and mRNA data for EGFR suggest post-transcriptional modification. Thus, phenobar-bitone caused transient replication of hepatocytes and modulation of growth stimulatory and inhibitory factors and their associated receptors in terms of overall levels and regional distribution in the liver.

Journal

CarcinogenesisOxford University Press

Published: May 1, 1996

There are no references for this article.