Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
1995-5-19
pubmed:abstractText
The expression pattern of mitochondrial carnitine palmitoyltransferase (CPT) enzymes was examined in the developing rat heart. Whereas the specific activity of CPT II increased approximately 3-fold during the first month of life, the profile for CPT I, which is composed of both liver (L) and muscle (M) isoforms, was more complex. Exposure of mitochondria to [3H]etomoxir (a covalent ligand for CPT I), followed by fluorographic analysis of the membrane proteins, established that while in the adult heart L-CPT I represents a very minor constituent, its contribution is much greater in the newborn animal. Use of the related inhibitor, 2-[6-(2,4-dinitrophenoxy)hexyl]oxirane-2-carboxylic acid (specific for L-CPT I), allowed the activities of the two CPT I variants to be quantified separately. The results showed that in the neonatal heart, L-CPT I contributes approximately 25% to total CPT I activity (in Vmax terms), the value falling during growth of the pups (with concomitant increasing expression of the M isoform) to its adult level of 2-3%. Because the myocardial carnitine content is very low at birth and rises dramatically over the next several weeks, it can be estimated that L-CPT I (Km for carnitine of only 30 microM compared with a value of 500 microM for M-CPT I) is responsible for some 60% of total cardiac fatty acid oxidation in the newborn rat; the value falls to approximately 4% in adult animals. Should these findings have a parallel in humans, they could have important implications for understanding the pathophysiological consequences of inherited L-CPT I deficiency syndromes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8952-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Mitochondrial carnitine palmitoyltransferase I isoform switching in the developing rat heart.
pubmed:affiliation
Department of Internal Medicine, University of Texas Southwestern Medical Center, Southwestern Medical School, Dallas 75235, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't