Dexamethasone suppresses the expression of multiple rat carboxylesterases through transcriptional repression: evidence for an involvement of the glucocorticoid receptor
Language: 
English
Short Title: 
Dexamethasone suppresses the expression of multiple rat carboxylesterases through transcriptional repression
Abstract: 

Carboxylesterases play important roles in the metabolism of xenobiotics and detoxication of insecticides. Without exception, all mammalian species studied express multiple forms of carboxylesterases. Several rat carboxylesterases are well-characterized including hydrolase A, B and S, and the expression of these enzymes is significantly suppressed by glucocorticoid dexamethasone. In this study, we used multiple experimental systems and presented a molecular mechanism for the suppression. Rats receiving one or more daily injections of dexamethasone consistently expressed lower HA, HB and HS. The suppression occurred at the levels of mRNA, protein and hydrolytic activity. In hepatoma cell line H4-II-E-C3, nanomolar dexamethasone caused significant decreases in HA, HB and HS mRNA, and the decreases were abolished by antiglucocorticoid RU486. Additionally, dexamethasone at nanomolar concentrations repressed the promoters of carboxylesterases, and the repression was reduced by glucocorticoid receptor-beta, a dominant negative regulator of the glucocorticoid receptor (GR). In contrast, co-transfection of the pregnane X receptor (PXR) increased the reporter activities, but the increase occurred only at micromolar concentrations of dexamethasone. These findings establish that both GR and PXR are involved in the regulated expression of rat carboxylesterases by dexamethasone but their involvement depends on the concentrations.

Author(s): 
Shi, Deshi
Yang, Jian
Yang, Dongfang
Yan, Bingfang
Item Type: 
Journal Article
Publication Title: 
Toxicology
Journal Abbreviation: 
Toxicology
Publication Date: 
Dec 5, 2008
Publication Year: 
2008
Pages: 
97-105
Volume: 
254
Issue: 
1-2
ISSN: 
0300-483X
DOI: 
10.1016/j.tox.2008.09.019
Library Catalog: 
NCBI Published Medical (?)
Extra: 
PMID: 18938207 PMCID: PMC2656940

Turabian/Chicago Citation

Deshi Shi, Jian Yang, Dongfang Yang and Bingfang Yan. Dec 5, 2008. "Dexamethasone suppresses the expression of multiple rat carboxylesterases through transcriptional repression: evidence for an involvement of the glucocorticoid receptor." Toxicology 254: 1-2: 97-105. 10.1016/j.tox.2008.09.019.

Wikipedia Citation

<ref> {{Cite journal | doi = 10.1016/j.tox.2008.09.019 | issn = 0300-483X | volume = 254 | pages = 97-105 | last = Shi | first = Deshi | coauthors = Yang, Jian, Yang, Dongfang, Yan, Bingfang | title = Dexamethasone suppresses the expression of multiple rat carboxylesterases through transcriptional repression: evidence for an involvement of the glucocorticoid receptor | journal = Toxicology | date = Dec 5, 2008 | pmid = | pmc = }} </ref>