Blood compartmental metabolism of docosahexaenoic acid (DHA) in humans after ingestion of a single dose of [(13)C]DHA in phosphatidylcholine.
The amount and distribution of [(13)C]docosahexaenoic acid (DHA) in plasma, platelet, and erythrocyte lipid classes were followed as a function of time (1 to 72 h) in young adults after ingestion of a single dose of [(13)C]DHA esterified in a phosphatidylcholine (PC), in using gas chromatography combustion;-isotope ratio mass spectrometry. [(13)C]DHA first appeared in plasma non-esterified fatty acids (NEFA) and triglycerides (TG), with a maximal appearance at 6 h and a further decline, then being delayed 3-fold compared to [(13)C]DHA ingested in triglycerides. Lysophosphatidylcholine (LPC) was also enriched in [(13)C]DHA, due mainly to earlier hepatic secretion, and plateaued at 6 h, whereas phosphatidylethanolamine (PE) and phosphatidylcholine (PC) containing [(13)C]DHA plateaued at 9 h. The labeling of erythrocyte and platelet phospholipids exhibited different kinetics, probably involving different metabolic pathways for [(13)C]DHA incorporation in cell membranes. Computation of the relative contribution of LPC and NEFA for delivery of [(13)C]DHA to blood cells showed that the supply to platelets occurred through NEFA. In contrast, [(13)C]DHA was carried by both LPC and NEFA to erythrocytes, which differs from what was previously been observed after intake of triglycerides labeled with [(13)C]DHA where LPC was the only source of [(13)C]DHA for erythrocytes. We conclude that the lipid form of ingested DHA affects markedly its kinetics and partly its metabolic fate.
Lemaitre-Delaunay
D
D
INSERM U352, Biochimie & Pharmacologie, INSA-Lyon, Villeurbanne, France.
Pachiaudi
C
C
Laville
M
M
Pousin
J
J
Armstrong
M
M
Lagarde
M
M
D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid; D004041:Dietary Fats; D004281:Docosahexaenoic Acids / Q000097:blood* / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D010713:Phosphatidylcholines / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood
D002247:Carbon Isotopes; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D010713:Phosphatidylcholines; D014280:Triglycerides; D004281:Docosahexaenoic Acids