Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2010-3-15
pubmed:abstractText
Docosahexaenoic acid (DHA) regulates the expression of cytochrome P450 2B1 (CYP 2B1) in rat primary hepatocytes in response to xenobiotics. Ceramide, a lipid signaling molecule, is involved in various physiological processes and can be generated by the hydrolysis of sphingomyelin via sphingomyelinase (SMase). DHA activates SMase and increases ceramide formation in vitro. Ceramides differentially enhance adenylyl cyclase activity in vitro depending on the chain length of their fatty acids. In addition, the cAMP-dependent PKA pathway down-regulates CYP 2B1 expression induced by phenobarbital (PB). In the present study, we determined the effect of DHA on SMase transactivation and the downstream pathway in CYP 2B1 expression induced by PB. SMase was activated by DHA 2 h after treatment, and D609 (an SMase inhibitor) attenuated the inhibition of PB-induced CYP 2B1 expression by DHA. Ceramide formation reached a maximum 3 h after DHA administration. C2-ceramide dose-dependently inhibited PB-induced CYP 2B1 expression and increased intracellular cAMP concentrations. SQ22536 (an adenylyl cyclase inhibitor) and H89 (a PKA-specific inhibitor) partially reversed the inhibition of PB-induced CYP 2B1 expression by C2-ceramide. These results suggest that stimulation of SMase, generation of ceramide and activation of the cAMP-dependent PKA pathway are involved in the inhibition exerted by DHA.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1873-4847
pubmed:author
pubmed:copyrightInfo
Copyright 2010 Elsevier Inc. All rights reserved.
pubmed:issnType
Electronic
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
338-44
pubmed:meshHeading
pubmed-meshheading:19427778-Adenylate Cyclase, pubmed-meshheading:19427778-Animals, pubmed-meshheading:19427778-Cells, Cultured, pubmed-meshheading:19427778-Ceramides, pubmed-meshheading:19427778-Cyclic AMP, pubmed-meshheading:19427778-Cyclic AMP-Dependent Protein Kinases, pubmed-meshheading:19427778-Cytochrome P-450 CYP2B1, pubmed-meshheading:19427778-Docosahexaenoic Acids, pubmed-meshheading:19427778-Down-Regulation, pubmed-meshheading:19427778-Hepatocytes, pubmed-meshheading:19427778-Male, pubmed-meshheading:19427778-Phenobarbital, pubmed-meshheading:19427778-Rats, pubmed-meshheading:19427778-Rats, Sprague-Dawley, pubmed-meshheading:19427778-Signal Transduction, pubmed-meshheading:19427778-Sphingomyelin Phosphodiesterase, pubmed-meshheading:19427778-Sphingosine, pubmed-meshheading:19427778-Time Factors, pubmed-meshheading:19427778-Transcriptional Activation
pubmed:year
2010
pubmed:articleTitle
Docosahexaenoic acid down-regulates phenobarbital-induced cytochrome P450 2B1 gene expression in rat primary hepatocytes via the sphingomyelinase/ceramide pathway.
pubmed:affiliation
Department of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't