Simultaneous quantitative determination of deuterium- and carbon-13-labeled essential fatty acids in rat plasma.
This study reports methods for the quantitative determination of stable isotope-labeled essential fatty acids (EFAs) as well as an experiment in which deuterium-labeled linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) were compared with those labeled with carbon-13 in rat plasma in vivo. Standard curves were constructed to compensate for concentration and plasma matrix effects. It was observed that endogenous pools of fatty acids had a greater suppressing effect on the measurements of 13C-U-labeled EFAs relative to those labeled with 2H5. Using these methods, the in vivo metabolism of orally administered deuterated-linolenate, 13C-U-labeled linolenate, deuterated-linoleate, and 13C-U-labeled linoleate was compared in adult rats (n = 11). There were no significant differences in the concentrations of the 2H versus 13C isotopomers of 18:2n-6, 18:3n-3, arachidonic acid (20:4n-6), and docosahexaenoic acid (22:6n-3) in rat plasma samples at 24 h after dosing. Thus, there appears to be little isotope effect for 2H5- versus 13C-U-labeled EFAs when the data are calculated using the conventional standard curves and corrected for endogenous fatty acid pool size and matrix effects.
Lin
Yu Hong
YH
Section of Nutritional Neuroscience, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9410, USA.
Pawlosky
Robert J
RJ
Salem
Norman
N
D000818:Animals; D016718:Arachidonic Acid / Q000097:blood; D002247:Carbon Isotopes; D002849:Chromatography, Gas / Q000379:methods; D003903:Deuterium; D004281:Docosahexaenoic Acids / Q000097:blood; D005228:Fatty Acids, Essential / Q000097:blood* / Q000493:pharmacokinetics; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D007553:Isotope Labeling; D019787:Linoleic Acid / Q000097:blood; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017962:alpha-Linolenic Acid / Q000097:blood
D002247:Carbon Isotopes; D005228:Fatty Acids, Essential; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; D019787:Linoleic Acid; D003903:Deuterium