Linked Life Data

18422600

Source:http://linkedlifedata.com/resource/pubmed/id/18422600

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2008-8-21
pubmed:abstractText
(Pre)neoplastic lesions in livers of rats induced by diethylnitrosamine are characterized by elevated activity of the first irreversible enzyme of the oxidative branch of the pentose phosphate pathway (PPP), glucose-6-phosphate dehydrogenase (G6PD), for production of NADPH. In the present study, the activity of G6PD, and the other NADPH-producing enzymes, phosphogluconate dehydrogenase (PGD), isocitrate dehydrogenase (ICD) and malate dehydrogenase (MD) was investigated in (pre)neoplastic lesions by metabolic mapping. Transketolase (TKT), the reversible rate-limiting enzyme of the non-oxidative branch of the PPP, mainly responsible for ribose production, was studied as well. Activity of G6PD in (pre)neoplastic lesions was highest, whereas activity of PGD and ICD was only 10% and of MD 5% of G6PD activity, respectively. Glucose-6-phosphate dehydrogenase activity in (pre)neoplastic lesions was increased 25 times compared with extralesional parenchyma, which was also the highest activity increase of the four NADPH-producing dehydrogenases. Transketolase activity was 0.1% of G6PD activity in lesions and was increased 2.5-fold as compared with normal parenchyma. Transketolase activity was localized by electron microscopy exclusively at membranes of granular endoplasmic reticulum in rat hepatoma cells where G6PD activity is localized as well. It is concluded that NADPH in (pre)neoplastic lesions is mainly produced by G6PD, whereas elevated TKT activity in (pre)neoplastic lesions is responsible for ribose formation with concomitant energy supply by glycolysis. The similar localization of G6PD and TKT activity suggests the channelling of substrates at this site to optimize the efficiency of NADPH and ribose synthesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1365-2613
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
232-40
pubmed:meshHeading
pubmed-meshheading:18422600-Animals, pubmed-meshheading:18422600-Cell Line, Tumor, pubmed-meshheading:18422600-Diethylnitrosamine, pubmed-meshheading:18422600-Enzyme Activation, pubmed-meshheading:18422600-Glucosephosphate Dehydrogenase, pubmed-meshheading:18422600-Image Processing, Computer-Assisted, pubmed-meshheading:18422600-Isocitrate Dehydrogenase, pubmed-meshheading:18422600-Liver, pubmed-meshheading:18422600-Liver Neoplasms, pubmed-meshheading:18422600-Malate Dehydrogenase, pubmed-meshheading:18422600-Male, pubmed-meshheading:18422600-Microscopy, Electron, pubmed-meshheading:18422600-Models, Animal, pubmed-meshheading:18422600-NADP, pubmed-meshheading:18422600-Oxidation-Reduction, pubmed-meshheading:18422600-Pentose Phosphate Pathway, pubmed-meshheading:18422600-Phosphogluconate Dehydrogenase, pubmed-meshheading:18422600-Precancerous Conditions, pubmed-meshheading:18422600-Rats, pubmed-meshheading:18422600-Rats, Wistar, pubmed-meshheading:18422600-Ribose, pubmed-meshheading:18422600-Transketolase
pubmed:year
2008
pubmed:articleTitle
Elevated activity of the oxidative and non-oxidative pentose phosphate pathway in (pre)neoplastic lesions in rat liver.
pubmed:affiliation
Academic Medical Center, University of Amsterdam, Department of Cell Biology and Histology, Amsterdam, The Netherlands. w.m.frederiks@amc.uva.nl
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't