Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism by which enoximone, a reported phosphodiesterase inhibitor, inhibits the oxidation of long-chain fatty acids was studied in isolated rat heart mitochondria using a series of 14C-labeled substrates. Enoximone decreased palmitate oxidation in a time- and concentration-dependent manner. Fifty percent inhibition of palmitate oxidation was achieved with 250 microM of enoximone. In contrast to its effect on palmitate, enoximone (250 microM) increased octanoate oxidation by 30%, whereas pyruvate oxidation was unaffected by enoximone. At that dose there was no effect on the oxidation of palmitoyl-CoA and palmitoyl carnitine. The degree of palmitate oxidation inhibited by enoximone was parallel to the inhibition of acyl-CoA synthetase in both rat heart mitochondria and microsomes. These results suggest that enoximone is a reversible inhibitor of long-chain fatty acyl-CoA synthetase. Moreover, the reaction, which is catalyzed by this enzyme, is a rate-limiting step in the pathway of fatty acid oxidation in rat heart mitochondria.
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PMID:The inhibition of long-chain fatty acyl-CoA synthetase by enoximone in rat heart mitochondria. 137 10

Biopharmacological evaluations of the protective effects of L-carnitine (a naturally occurring quaternary ammonium compound) against doxorubicin-induced metabolic damage were carried out in isolated cardiac myocytes and in isolated rat heart mitochondria. Perfusion of the heart with DOX (0.5 mM) caused a significant 70% inhibition of palmitate oxidation in cardiac myocytes, while L-carnitine (5 mM) perfusion caused stimulation which accounted for 37%. Perfusion of the heart with L-carnitine after 10-min perfusion with DOX (0.5 mM) caused 88% reversal of DOX-induced inhibition of palmitate oxidation in cardiac cells. In rat heart mitochondria, DOX has no effect on either palmitate oxidation or acyl-CoA synthetase activity, whereas Enoximone (c-AMP-dependent phosphodiesterase inhibitor), caused a significant inhibition of palmitate oxidation and acyl-CoA activity (40 and 27%, respectively). The oxidation of palmitoyl-CoA, an index of carnitine palmitoyltransferse reaction was significantly inhibited by DOX as a function of DOX concentration. Preincubation of mitochondria with L-carnitine caused reversal of DOX-induced inhibition of palmitoyl-CoA oxidation depending on the concentration of L-carnitine. Moreover, L-carnitine treatment did not interfere with the cytotoxic effect of doxorubicin against the growth of solid Ehrlich carcinoma. The findings of this study may suggest that inhibition of fatty acid oxidation in the heart is at least a part of doxorubicin cardiotoxicity and that L-carnitine can be used to prevent the doxorubcin-induced cardiac metabolic damage without interfering with its antitumour activities.
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PMID:Reversal of doxorubicin-induced cardiac metabolic damage by L-carnitine. 1020 59