scholarly journals Functional loss of ketogenesis in odontocete cetaceans

Author(s):  
Michael J. Wolfgang ◽  
Joseph Choi ◽  
Susanna Scafidi

Odontocete cetaceans exhibit genomic mutations in key ketogenesis genes. In order to validate an inferred lack of ketogenesis made by observations from genome sequencing, we biochemically analyzed tissues from several odontocete cetacean species and demonstrate that they indeed do not exhibit appreciable hepatic β-hydroxybutyrate (βHB) or its carnitine ester. Furthermore, liver tissue exhibited significantly lower long chain acylcarnitines and increased odd chain acylcarnitines indicative of a decreased reliance on hepatic long chain fatty acid oxidation in these carnivorous mammals. Finally, we performed Single Molecule, Real-Time next generation sequencing of liver and brain RNA of T. truncatus and demonstrate that the succinyl-CoA transferase required for acetoacetate catabolism is expressed in the nervous system. These data show that odontocete cetaceans have lost the ability to perform ketogenesis and suggest a hepatocentric Coenzyme A recycling function rather than a predominantly systemic-bioenergetic role for ketogenesis in other ketogenic competent mammals like humans.

Cell Reports ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 3300-3311 ◽  
Author(s):  
Linford J.B. Briant ◽  
Michael S. Dodd ◽  
Margarita V. Chibalina ◽  
Nils J.G. Rorsman ◽  
Paul R.V. Johnson ◽  
...  

1990 ◽  
Vol 258 (1) ◽  
pp. H51-H56 ◽  
Author(s):  
S. E. Litwin ◽  
T. E. Raya ◽  
R. G. Gay ◽  
J. B. Bedotto ◽  
J. J. Bahl ◽  
...  

This study was designed to determine the changes in the heart that result from inhibition of long-chain fatty acid oxidation with 2-tetradecylglycidic acid (TDGA). Male Sprague-Dawley rats (n = 64) were treated with TDGA (20 mg.kg-1.day-1) or a comparable volume of vehicle by gavage feeding for 7 or 21 days. In conscious rats TDGA produced no changes in heart rate, left ventricular systolic or end-diastolic pressures, left ventricular pressure development (dP/dt), or the time constant of left ventricular relaxation. Left ventricular developed pressure was not changed at 21 days. TDGA increased left ventricular weight, left ventricular weight-to-body weight ratio, and total heart weight-to-body weight ratio. Left ventricular endocardial and epicardial myocyte volumes were increased by 53 and 65%, respectively. Myocardial triglyceride content was increased threefold. Left ventricular chamber stiffness constants between end-diastolic pressures of 0 and 30 mmHg were increased, and left ventricular end-diastolic volumes at operating end-diastolic pressures were decreased at both 7 and 21 days. The myocardial stiffness constant was also increased at 7 and 21 days. Thus inhibition of long-chain fatty acid oxidation with TDGA increased left ventricular mass and altered left ventricular chamber and muscle stiffness without changing left ventricular relaxation or systolic function. We conclude that inhibition of long-chain fatty acid oxidation produced an unusual model of left ventricular hypertrophy and diastolic dysfunction characterized by abnormalities of passive-elastic properties but preserved relaxation.


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