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F E Hull

Publications and source records attributed to F E Hull.

12 recordsLinked to original sources
PubMed1986

beta-Hydroxy acyl-CoA inhibition of mitochondrial ATP production.

beta-Hydroxypalmitoyl-CoA and beta-hydroxystearoyl-CoA were synthesized, purified and quantitated. beta-Hydroxypalmitoyl-CoA and beta-hydroxystearoyl-CoA instantly and reversibly inhibited oxidative phosphorylation by rabbit heart mitochondria oxidizing pyruvate. [8-14C]ADP uptake studies showed that the beta-hydroxy acyl-CoA species linearly inhibited the adenine nucleotide translocase system. Free beta-hydroxy fatty acids at comparable concentrations (0.005 mM) did not affect ADP uptake or state III respiration.

Acyl Coenzyme A↗
PubMed1982

beta-Hydroxy fatty acid production by ischemic rabbit heart.

beta-Hydroxymyristate, -palmitate, and -stearate were produced by and accumulated in isolated rabbit heart when perfused ischemically for 2-10 min by the nonrecirculating langendorff technique with 0.75 mM palmitate and 0.16 mM albumin. Tissue fractionation into mitochondria and cytosol showed that by 2 min of ischemia 44% of beta-hydroxypalmitate and 38% beta-hydroxystearate was located in the cytosol; this percentage increased to greater than 50% by 5 min of ischemia. Lipid fractionation studies showed that by 10 min these two beta-hydroxy fatty acids were distributed approximately as 60% acylcarnitine, 20% acyl-coenzyme A (CoA), and 20% free fatty acids. All three chemical forms of beta-hydroxypalmitate were found in both the mitochondria and the cytosol. After 10 min of ischemia beta-hydroxypalmitoyl-CoA and beta-hydroxystearoyl-CoA constituted at least 16% of the incremental long-chain acyl-CoA, whereas beta-hydroxypalmitoylcarnitine and b-hydroxystearoylcarnitine constituted 8% of the incremental long-chain acylcarnitine. These data suggests that myocardial beta-hydroxyacyl-CoA oxidation is limited during ischemia. Substrate accumulates and is transferred to the cytosol where it accumulates primarily as beta-hydroxyacylcarnitine.

Animals↗
PubMed1980

Incomplete fatty acid oxidation by ischemic heart: beta-hydroxy fatty acid production.

A quantitative gas chromatography-mass spectrometry (GC/MS) method was developed to measure nanomolar quantities of long-chain saturated beta-hydroxy fatty acids (12, 14, 16, and 18 carbons long) produced by isolated ischemic heart. Only beta-hydroxymyristate (25-40 nmol/g dry) was found in fresh heart. Isolated rabbit heart perfused with fatty acid by the nonrecirculating Langendorff technique produced negligible beta-hydroxy fatty acids. Ischemic perfusion with 0.25-0.75 mM palmitate prompted heart beta-hydroxy fatty acid accumulation, beta-hydroxypalmitate greater than beta-hydroxystearate, up to 100 nmol x g dry-1 x 10 min-1. beta-Hydroxy fatty acid production was proportional to coronary effluent lactate-to pyruvate ratio, did not continue beyond 10 min of ischemia, was dependent on exogenous fatty acid, and was inhibited by coperfusion with 10 mM acetate. Reperfusion for 5-10 min dissipated accumulated beta-hydroxypalmitate. Hypoxic perfusion prompted beta-hydroxy fatty acid production comparable to that with severe ischemia. These data show that during oxygen deficiency heart fatty acid beta-oxidation is not only depressed but is also incomplete; beta-hydroxy fatty acyl intermediates accumulate and contribute to the increased intracellular fatty acid content characteristic of the ischemic myocardium.

Animals↗
PubMed1975

beta-Hydroxy fatty acid production during fatty acid oxidation by heart mitochondria.

The effect of various incubation conditions on the production of beta-hydroxylaurate, -myristate, and -palmitate by isolated rabbit heart mitochondria oxidizing palmityl carnitine was studied. A gas chromatographic-mass spectrometric method was developed to identify and measure submicrogram quantities of methyl esters of these beta-hydroxy fatty acids (FA). Alpha-Deuterated esters of beta-hydroxy-FA served as internal standards. The total amount of the three beta-hydroxy-FA in fresh mitochondria was 0.045 mug/mg of protein. Malate, ATP, rotenone, and 1-carnitine together effected an NADH:NAD ratio of 8 and the accumulation of 0.896 mug of beta-hydroxylpalmitate. Omission of carnitine decreased the beta-hydroxy-FA by 65 percent. Omission of palmityl carnitine resulted in no beta-hydroxy-FA. Without rotenone the NADH:NAD ratio was 0.5 and there accumulated only 0.085 mug of beta-hydroxy-FA/mg of protein/10 min. Succinate, in place of malate, effected an NADH:NAD ratio greater than 10 but only 0.465 mug of beta-hydroxy-FA/mg of protein/10 min. We conclude that elevated mitochondrial NADH:NAD ratios facilitate beta-hydroxy-FA accumulation by slowing beta-hydroxyacyl-CoA oxidation. Cardiac hypoxia may prompt beta-hydroxy-FA accumulation and/or release.

Animals↗
PubMed1975

Fatty acid oxidation by ischemic myocardium.

Ischemia markedly depresses fatty acid oxidation and increases fatty acyl-CoA and fatty acylcarnitine levels in the isolated heart during palmitate oxidation. Evidence suggests that the major defect is impaired beta-oxidation due to decreased electron transport rather than to diminished fatty acyl uptake, activation, or intramitochondrial transfer. Important metabolic effects may include decreased mitochondrial adenine nucleotide translocation and altered carnitine-palmity-l-CoA transferase activity.

Animals↗