Regulation of lysophosphatidylcholine-metabolizing enzymes in isolated myocardial cells from rat heart

1985 ◽  
Vol 63 (8) ◽  
pp. 944-951 ◽  
Author(s):  
David L. Severson ◽  
Thea Fletcher
Keyword(s):  
Fatty Acids ◽  
Palmitic Acid ◽  
Free Fatty Acids ◽  
Rat Heart ◽  
Marked Reduction ◽  
Myocardial Cells ◽  
Acyltransferase Activity ◽  
Metabolizing Enzymes ◽  
Enzymatic Pathways ◽  
Lysophospholipase Activity

Enzymatic pathways involved in the metabolism of lysophosphatidylcholine were investigated in rat heart myocardial cells. Acyl CoA-dependent acyltransferase activity was localized in microsomes, and was much greater than lysophospholipase activity in either cytosolic or microsomal fractions. The cytosolic lysophospholipase was more sensitive to inhibition by palmitylcarnitine in comparison to free fatty acids. In contrast, free fatty acids (oleate and palmitate) produced a greater inhibition of the microsomal acyltransferase and lysophospholipase than did palmitylcarnitine. A reduction in the assay pH to 6.5 resulted in an increase in microsomal acyltransferase and cytosolic lysophospholipase activities, but brought about a marked reduction in the microsomal lysophospholipase activity. At pH 6.5, the percentage inhibition of the microsomal acyltransferase by palmitylcarnitine was reduced, whereas the inhibition by palmitic acid was enhanced. The inhibition of the microsomal lysophospholipase by both palmitylcarnitine and palmitic acid was reduced at pH 6.5. With respect to myocardial ischemia, the inhibition of microsomal acyltransferase by free fatty acids and the reduction in microsomal lysophospholipase activity due to acidosis may contribute to the elevation of cellular lysophosphoglycerides which are arrhythmogenic.

scholarly journals EFFECTS OF CORTISOL ON CULTURED RAT HEART CELLS

1973 ◽  
Vol 57 (1) ◽  
pp. 109-116 ◽  
Author(s):  
J. V. Anastasia ◽  
R. L. McCarl
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Fatty Acid Oxidation ◽  
Growth Medium ◽  
Rat Heart ◽  
Acid Oxidation ◽  
Heart Cells ◽  
Atp Production ◽  
Rat Heart Cells

This paper reports the determination of the ability of rat heart cells in culture to release [14C]palmitate from its triglyceride and to oxidize this fatty acid and free [14C]palmitate to 14CO2 when the cells are actively beating and when they stop beating after aging in culture. In addition, the levels of glucose, glycogen, and ATP were determined to relate the concentration of these metabolites with beating and with cessation of beating. When young rat heart cells in culture are actively beating, they oxidize free fatty acids at a rate parallel with cellular ATP production. Both fatty acid oxidation and ATP production remain constant while the cells continue to beat. Furthermore, glucose is removed from the growth medium by the cells and stored as glycogen. When cultured cells stop beating, a decrease is seen in their ability to oxidize free fatty acids and to release them from their corresponding triglycerides. Concomitant with decreased fatty acid oxidation is a decrease in cellular levels of ATP until beating ceases. Midway between initiation of cultures and cessation of beating the cells begin to mobilize the stored glycogen. When the growth medium is supplemented with cortisol acetate and given to cultures which have ceased to beat, reinitiation of beating occurs. Furthermore, all decreases previously observed in ATP levels, fatty acid oxidation, and esterase activity are restored.

scholarly journals High rates of [1-14C]acetate incorporation into the lipid of isolated spinach chloroplasts

1976 ◽  
Vol 158 (3) ◽  
pp. 593-601 ◽  
Author(s):  
P G Roughan ◽  
C R Slack ◽  
R Holland
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Free Fatty Acids ◽  
Acid Synthesis ◽  
Polar Lipids ◽  
Acetate Incorporation ◽  
Spinach Chloroplasts ◽  
Triton X

Spinach chloroplasts, isolated by techniques yielding preparations with high O2- evolving activity, showed rates of light-dependent acetate incorporation into lipids 3-4 fold higher than any previously reported. Incorporation rates as high as 500 nmol of acetate/h per mg of chlorophyll were measured in buffered sorbitol solutions containing only NaHCO3 and [1-14C]acetate, and as high as 800 nmol/h per mg of chlorophyll when 0.13 mM-Triton X-100 was also included in the reaction media. The fatty acids synthesized were predominantly oleic (70-80% of the total fatty acid radioactivity) and palmitic (20-25%) with only minor amounts (1-5%) of linoleic acid. Linolenic acid synthesis was not detected in the system in vitro. Free fatty acids accounted for 70-90% of the radioactivity incorporated and the remainder was shared fairly evenly between 1,2-diacylglycerols and polar lipids. Oleic acid constituted 80-90% of the free fatty acids synthesized, but the diacylglycerols and polar lipids contained slightly more palmitic acid than oleic acid. Triton X-100 stimulated the synthesis of diacylglycerols 3-6 fold, but stimulated free fatty acid synthesis only 1-1.5-fold. Added glycerol 1-phosphate stimulated both the synthesis of diacylglycerols and palmitic acid relative to oleic acid, but did not increase acetate incorporation into total chloroplast lipids. CoA and ATP, when added separately, stimulated acetate incorporation into chloroplast lipids to variable extents and had no effect on the types of lipid synthesized, but when added together resulted in 34% of the incorporated acetate appearing in long-chain acyl-CoA. Pyruvate was a much less effective precursor of chloroplast fatty acids than was acetate.

Lipid Absorption and Deposition in Rainbow Trout (Salmo gairdnerii)

1973 ◽  
Vol 51 (7) ◽  
pp. 1050-1058 ◽  
Author(s):  
J. Stephen Robinson ◽  
James F. Mead
Keyword(s):  
Fatty Acids ◽  
Rainbow Trout ◽  
Palmitic Acid ◽  
Free Fatty Acids ◽  
Intestinal Absorption ◽  
Lipid Absorption ◽  
Portal System ◽  
Absorption Mechanism ◽  
Dark Muscle ◽  
Muscle Lipids

Rainbow trout, fed or starved for 5 weeks, were force-fed 23 μCi 1-14C-palmitic acid and sacrificed at [Formula: see text], 1, 2, 4, 8, and 14 h after feeding. Analysis of the blood suggested that trout possess an intestinal absorption mechanism for lipid that is very different from that found in other animals. The fish, incapable of delivering triglyceride to its circulation in the usual way, receives most of its absorbed lipid as free fatty acids, probably via the portal system. It was also found that light muscle more easily yielded its triglyceride stores, in agreement with its role as the major lipid depot in trout. Nonetheless, dark muscle was metabolically more active in deposition of muscle lipids. Dark muscle appeared to function more as an organ than a kinetically responsible contractile body.

Methylamine does not inhibit rates of endogenous lipolysis in isolated myocardial cells from rat heart

1987 ◽  
Vol 65 (2) ◽  
pp. 226-229 ◽  
Author(s):  
Albert Kryski Jr. ◽  
Terje S. Larsen ◽  
Ignasi Ramírez ◽  
David L. Severson
Keyword(s):  
Fatty Acids ◽  
Lipase Activity ◽  
Rat Heart ◽  
Diabetic Rat ◽  
Myocardial Cells ◽  
Acid Lipase ◽  
Ph Optimum ◽  
Triacylglycerol Lipase ◽  
Rat Hearts ◽  
Lysosomotropic Agent

Triacylglycerol lipase activity with a pH optimum of 5 was present in homogenates of myocardial cells from rat heart. Acid lipase activity was inhibited by serum, heparin, and increased ionic strength. Methylamine, a lysosomotropic agent, did not inhibit the basal or isoproterenol-stimulated rate of endogenous lipolysis as measured by glycerol output from control myocytes. Similarly, accelerated rates of glycerol output that are a consequence of an elevation in the intracellular stores of triacylglycerols in myocytes from diabetic rat hearts and from myocytes prepared with free fatty acids in the isolation solutions were not reduced by methylamine. Therefore, the acid lysosomal triacylglycerol lipase must not be involved in the mobilization of endogenous triacylglycerols in myocardial cells from rat heart.

Free fatty acids in human cerebrospinal fluid following subarachnoid hemorrhage and their potential role in vasospasm: a preliminary observation

2002 ◽  
Vol 97 (2) ◽  
pp. 272-279 ◽  
Author(s):  
Julie G. Pilitsis ◽  
William M. Coplin ◽  
Michael H. O'Regan ◽  
Jody M. Wellwood ◽  
Fernando G. Diaz ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cerebrospinal Fluid ◽  
Linoleic Acid ◽  
Subarachnoid Hemorrhage ◽  
Palmitic Acid ◽  
Free Fatty Acids ◽  
Potential Role ◽  
The Other ◽  
Content Type ◽  
Fine Print

Object. The mechanisms leading to vasospasm following subarachnoid hemorrhage (SAH) remain unclear. Accumulation in cerebrospinal fluid (CSF) of free fatty acids (FFAs) may play a role in the development of vasospasm; however, in no previous study have concentrations of FFAs in CSF been examined after SAH. Methods. We collected samples of CSF from 20 patients with SAH (18 cases of aneurysmal SAH and two cases of spontaneous cryptogenic SAH) and used a high-performance liquid chromatography assay to determine the FFA concentrations in these samples. We then compared these findings with FFA concentrations in the CSF of control patients. All FFA concentrations measured 24 hours after SAH were significantly greater than control concentrations (p < 0.01 for palmitic acid and < 0.001 for all other FFAs). All measured FFAs remained elevated for the first 48 hours after SAH (p < 0.05 for linoleic acid, p < 0.01 for palmitic acid, and p < 0.001 for the other FFAs). After 7 days, a second elevation in all FFAs was observed (p < 0.05 for linoleic acid, p < 0.01 for palmitic acid, and p < 0.001 for the other FFAs). Samples of CSF collected within 48 hours after SAH from patients in whom angiography and clinical examination confirmed the development of vasospasm after SAH were found to have significantly higher concentrations of arachidonic, linoleic, and palmitic acids than samples collected from patients in whom vasospasm did not develop (p < 0.05). Conclusions. Following SAH, all FFAs are initially elevated. A secondary elevation occurs between 8 and 10 days after SAH. This study provides preliminary evidence of FFA elevation following SAH and of a potential role for FFAs in SAH-induced vasospasm. A prospective study is warranted to determine if CSF concentrations of FFAs are predictive of vasospasm.

DEPRESSION OF CONTRACTILITY IN RAT HEART MUSCLE BY FREE FATTY ACIDS DURING HYPOXIA

The Lancet ◽  
1969 ◽  
Vol 294 (7625) ◽  
pp. 825-826 ◽  
Author(s):  
A.H Henderson ◽  
A.S Most ◽  
E.H Sonnenblick
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Heart Muscle ◽  
Rat Heart
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