Comparison of catabolism rate of fatty acids to carbon dioxide in mice

Abstract

The catabolism rates of a medium chain fatty acid (octanoic acid), an even‐numbered fatty acid (palmitic acid), and odd‐numbered fatty acids (pentadecanoic acid and heptadecanoic acid) in mice were compared using stable isotope (13C) labeled fatty acids and isotope‐ratio MS (IRMS). The catabolism rates of respective fatty acids were evaluated by the ratio of 13C and 12C in carbon dioxide expired from mice. The results show that the catabolism rate of octanoic acid is three times faster than that of palmitic acid. This result is in agreement with previous knowledge that medium chain fatty acids are easily beta‐oxidized as compared to long chain fatty acids. The catabolism rates of odd‐numbered fatty acids such as pentadecanoic acid and heptadecanoic acid were significantly lower as compared to those of even‐numbered fatty acids such as palmitic acid. This finding supports our previous report that odd‐numbered fatty acids are easily accumulated into body fat. The high accumulation of odd‐numbered fatty acids in body fat would be a direct result of their low beta‐oxidizability.Practical applications: 13C‐labeled fatty acids were administered to mice and the rates of 13CO2 formation were compared among medium chain, even‐numbered, and odd‐numbered fatty acids using IRMS. We found that the catabolism rates of odd‐numbered fatty acids such as pentadecanoic acid and heptadecanoic acid were significantly lower in comparison to those of even‐numbered fatty acids such as palmitic acid. These findings could be valuable for the development of the lipid metabolism field.

Dietary Starfish Oil Prevents Hepatic Steatosis and Hyperlipidemia in C57BL/6N Mice Fed High-fat Diet

“…This method was newly arranged to measure the activation of fatty acid β-oxidation in our previous study 25 and can provide evidence as to whether consumption of SO enhances disposing diet-derived fatty acids.…”

“…The mice were fasted during sample collection. The actual ratio of 13 CO 2 / 12 CO 2 in the expired gas was analyzed using IR-MS ANCA-GSL, SerCon, Cheshire, UK and the catabolic rate of 13 C-PA was determined as described in our previous study 25 .…”

Comparison of Catabolic Rates of <i>sn</i>-1, <i>sn</i>-2, and <i>sn</i>-3 Fatty Acids in Triacylglycerols Using ¹³CO₂ Breath Test in Mice

“…13 CO 2 to 12 CO 2 in sampled gas The natural abundances of 13 C and 12 C in G1-grade CO 2 purchased from Taiyo Nippon Sanso Corporation Tokyo, Japan were analyzed by SI Science Co. Ltd., Sugito, Japan, δ 13 C-Vienna Pee Dee Belemnite VPDB 29.6 . The CO 2 was diluted 10 fold with nitrogen gas, and the mixed gas was packed into a 12-mL evacuated vial.…”

“…The mixed gas was used as a standard to adjust the value measured using isotope-ratio mass spectrometry IRMS ANCA-GSL, SerCon Ltd., Cheshire, UK . The ratio of 13 C to 12 C in the Fig. 2 Structures of TAG isomers used in this study.…”

<i>Trans</i>-octadecenoic Acid Positional Isomers Have Different Accumulation and Catabolism Properties in Mice

“…Whole-body oxidation of fatty acids has been measured by the administration of 13 C -labeled fatty acids followed by measurement of expired 13 CO 2 29, 30 . To elucidate whether the metabolic rate of each TFA isomer depended upon double-bond position, we fed mice with individual isomers and calculated Δ 13 C values from the carbon isotope ratios in expired CO 2 gas samples using an IRMS system 26,27 . Δ 13 C values rapidly increased in the first 90 min of labeled-TFA ingestion and peaked during 75-105 min in all test groups Fig.…”