scholarly journals Peroxisomal Citrate Synthase Provides Exit Route from Fatty Acid Metabolism in Oilseeds

2005 ◽  
Vol 17 (7) ◽  
pp. 1863-1865 ◽  
Author(s):  
Nancy A. Eckardt
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Citrate Synthase ◽  
Exit Route

Activity levels of enzymes of energy metabolism in heart and red muscle are higher in north-temperate-zone than in Amazonian teleosts

1999 ◽  
Vol 77 (5) ◽  
pp. 690-696 ◽  
Author(s):  
J L West ◽  
J R Bailey ◽  
VMF Almeida-Val ◽  
A L Val ◽  
B D Sidell ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Citrate Synthase ◽  
Temperate Zone ◽  
Activity Levels ◽  
Body Temperatures ◽  
Astronotus Ocellatus ◽  
Red Muscle

Fish living in the Amazon basin typically have body temperatures of about 30°C, whereas freshwater fishes of the north-temperate zone are eurythermal, with typical body temperatures of 10-20°C in summer. Enzyme activity levels in heart and red muscle of Amazonian species, which display various physiological mechanisms for dealing with hypoxic conditions, were compared with those in north-temperate-zone species. Five Amazonian species (acará-açu (Astronotus ocellatus), acari-bodó (Lipossarcus pardalis), tambaqui (Colossoma macropomum), tamoatá (Hoplosternum littorale), and pirarucu (Arapaima gigas)) and four north-temperate-zone species (American eel, bullhead, yellow perch, and rainbow trout) were studied. The Amazonian species included obligate and facultative air breathers. Activities of key indicator enzymes associated with carbohydrate metabolism, fatty acid metabolism, the citric acid cycle, and the electron-transport chain were determined. There was no obvious correlation between cardiac enzyme activity levels and the potential ability of fish to maintain blood oxygen levels in hypoxic water or the capacity of isolated heart preparations to survive anoxia. In heart, activity levels of hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase, citrate synthase, cytochrome oxidase, and β-hydroxyacyl CoA dehydrogenase were about twice as high in north-temperate-zone species than in Amazonian species. Activities of red-muscle enzymes, especially those associated with aerobic fatty acid metabolism, were significantly higher in comparable north-temperate-zone species relative to Amazonian species. Increased enzyme activity levels in north-temperate-zone species relative to Amazonian species is considered to be an adaptation to generally lower body temperatures. This finding is consistent with earlier comparisions of Antarctic and north-temperate-zone species and with the results of studies of cold acclimation within north-temperate-zone fishes.

Fatty acid metabolism in skeletal muscle mitochondria from two strains of dystrophic mice

1980 ◽  
Vol 58 (7) ◽  
pp. 549-558 ◽  
Author(s):  
M. E. Martens ◽  
C. P. Lee
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Citrate Synthase ◽  
Kinetic Measurements ◽  
Muscle Mitochondria ◽  
Normal Littermate ◽  
Skeletal Muscle Mitochondria ◽  
Severe Impairment

Several aspects of fatty acid metabolism have been examined in skeletal muscle mitochondria from both strain 129 dystrophic (dy/dy) and myodystrophic (myd/myd) mice. Skeletal muscle mitochondria from dy/dy mice showed significantly decreased state 3 respiratory rates with both palmityl- and acetyl-carnitine + malate as substrates when compared with their normal littermate controls. A similar, though less severe impairment in acylcarnitine oxidation by mitochondria from myd/myd skeletal muscle has also been shown by us in a previous study. In the present study, kinetic measurements revealed decreased activities of the reverse carnitine palmityltransferase (palmitylcarnitine + CoASH as substrates) in intact mitochondria from dy/dy muscle, and of citrate synthase in myd/myd muscle mitochondria. However, neither of these reactions appeared to be rate limiting for acylcarnitine oxidation in mouse skeletal muscle mitochondria. All other enzyme activities or cofactor contents measured were either comparable to those of controls or were higher. The results reported here indicate that neither of the impairments in acylcarnitine oxidation by skeletal muscle mitochondria from dy/dy or myd/myd mice is due to deficiencies in either carnitine palmityltransferase, carnitine acetyltransferase, citrate synthase, coenzyme A, or substrate-reducible flavoprotein.

The Influence of Lactate and Dipyridamole on Myocardial Fatty Acid Metabolism in Man, Traced with 123l-17-lodo-heptadecanoic Acid

1990 ◽  
Vol 29 (01) ◽  
pp. 28-34 ◽  
Author(s):  
F. C. Visser ◽  
M. J. van Eenige ◽  
G. Westera ◽  
J. P. Roos ◽  
C. M. B. Duwel
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Time Activity ◽  
Time Value ◽  
Myocardial Fatty Acid Metabolism ◽  
Coronary Vasodilatation ◽  
Activity Curve ◽  
Normal Human ◽  
Plasma Lactate Level

Changes in myocardial metabolism can be detected externally by registration of time-activity curves after administration of radioiodinated fatty acids. In this scintigraphic study the influence of lactate on fatty acid metabolism was investigated in the normal human myocardium, traced with 123l-17-iodoheptadecanoic acid (123l-17-HDA). In patients (paired, n = 7) lactate loading decreased the uptake of 123l-17-HDA significantly from 27 (control: 22-36) to 20 counts/min/pixel (16-31; p <0.05 Wilcoxon). The half-time value increased to more than 60 rriin (n = 5), oxidation decreased from 61 to 42%. Coronary vasodilatation, a well-known side effect of lactate loading, was studied separately in a dipyridamole study (paired, n = 6). Coronary vasodilatation did not influence the parameters of the time-activity curve. These results suggest that changes in plasma lactate level as occurring, among other effects, during exercise will influence the parameters of dynamic 123l-17-HDA scintigraphy of the heart.

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