scholarly journals The metabolism of phenolic acids in the rat

1974 ◽  
Vol 140 (3) ◽  
pp. 517-522 ◽  
Author(s):  
S. Ranganathan ◽  
T. Ramasarma
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Phenolic Acids ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Enzyme Systems

Some of the enzyme systems in the formation of p-hydroxybenzoate from tyrosine have been studied in the rat liver in vitro. The conversion of p-hydroxycinnamate into p-hydroxybenzoate, which was found in rat liver mitochondria showed a number of differences when compared with the β-oxidation of fatty acids. Studies with p-hydroxy[U-14C]cinnamate indicated that 14CO2 was released during the formation of p-hydroxybenzoate. The formation of p-hydroxycinnamate from tyrosine of p-hydroxyphenyl-lactate could not be demonstrated in vitro. The interconversion of p-hydroxycinnamate and p-hydroxyphenylpropionate was demonstrated in rat liver mitochondria.

Uncoupling activity of endogenous free fatty acids in rat liver mitochondria

1978 ◽  
Vol 56 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Samuel H. P. Chan ◽  
Edward Higgins Jr.
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Rat Liver ◽  
Respiratory Control ◽  
Aging Effect ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria

Changes in the respiratory control index (RCI) and ADP:O ratio were found to be related to alterations in the free fatty acids levels of rat liver mitochondria aging in 0.25 M sucrose–Tris buffer at 0 °C. Free fatty acid levels increased with time after isolation of mitochondria while a concomitant decrease in the RCI and ADP:O ratio occurred. The changes in free fatty acid levels corresponded with the reported increasing levels of phospholipase A activity in aged mitochondrial preparations. Washing these mitochondria with sucrose buffer containing 1% defatted bovine serum albumin (BSA) counteracted the aging effect on the RCI (e.g., 2.5 to 3.5) and reduced the free fatty acid levels (e.g., 50 to 16 nmol/mg protein). This reversible phenomenon could be repeated several times during the in vitro aging at 0 °C. Use of 125I-iodinated BSA showed that approximately 5 μg BSA/mg mitochondria was adsorbed by the mitochondrial membranes during washing. These results indicate a direct correlation between the level of endogenous fatty acids and the uncoupling of mitochondrial oxidative phosphorylation. The mechanism of counteracting the aging effect by BSA involves the removal of some of the free fatty acids.

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