Linked Life Data

11016633

Source:http://linkedlifedata.com/resource/pubmed/id/11016633

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2000-10-13
pubmed:abstractText
Connexin32 (Cx32) is the major gap junction forming protein in liver. We have recently shown that hepatocarcinogenesis is strongly enhanced in mice deficient in Cx32, demonstrating that lack of functional Cx32 accelerates liver tumorigenesis. Many tumor-promoting agents, including phenobarbital, block gap junctional intercellular communication in vitro, and it has been suggested that this effect is relevant for clonal expansion of neoplastic cells in vivo. We have now tested this hypothesis by analyzing the potency of phenobarbital as a liver tumor promoter in male Cx32-wild-type (Cx32(Y/+)) and Cx32-null (Cx32(Y/-)) mice. Preneoplastic and neoplastic liver lesions were induced in 6-week-old male mice by a single injection of 90 microg/g body weight of N-nitrosodiethylamine, and groups of mice were subsequently kept on phenobarbital-containing (0.05%) or control diet for 39 weeks. Frozen liver sections were prepared, and (pre)neoplastic lesions were identified by their deficiency in glucose-6-phosphatase staining. In addition, the number and size of macroscopically visible tumors were monitored. Phenobarbital led to a approximately 5-fold increase in the volume fraction occupied by glucose-6-phosphatase-deficient liver lesions in Cx32(Y/+) mice, whereas there was no such increase in Cx32(Y/-) mice. Even more pronounced differences were observed with respect to tumor response. Whereas phenobarbital clearly promoted the occurrence of numerous large hepatomas in Cx32(Y/+) mice, no such effect was seen in Cx32(Y/-) mice. These results demonstrate, for the first time, that functional Cx32 protein is required for tumor promotion by phenobarbital.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
60
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5087-91
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Lack of phenobarbital-mediated promotion of hepatocarcinogenesis in connexin32-null mice.
pubmed:affiliation
Institut für Toxikologie, Tübingen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't