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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
15
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pubmed:dateCreated |
1995-5-19
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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.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Apr
|
pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
14
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pubmed:volume |
270
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pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
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pubmed:pagination |
8952-7
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:7721804-Aging,
pubmed-meshheading:7721804-Animals,
pubmed-meshheading:7721804-Carnitine O-Palmitoyltransferase,
pubmed-meshheading:7721804-Cells, Cultured,
pubmed-meshheading:7721804-Female,
pubmed-meshheading:7721804-Heart,
pubmed-meshheading:7721804-Isoenzymes,
pubmed-meshheading:7721804-Kinetics,
pubmed-meshheading:7721804-Male,
pubmed-meshheading:7721804-Mitochondria, Heart,
pubmed-meshheading:7721804-Myocardium,
pubmed-meshheading:7721804-Rats,
pubmed-meshheading:7721804-Rats, Sprague-Dawley
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pubmed:year |
1995
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pubmed:articleTitle |
Mitochondrial carnitine palmitoyltransferase I isoform switching in the developing rat heart.
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pubmed:affiliation |
Department of Internal Medicine, University of Texas Southwestern Medical Center, Southwestern Medical School, Dallas 75235, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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