Role of Liver and Plasma Lipoproteins in Selective Transport of n-3 Fatty Acids to Tissues: A Comparative Study of ¹⁴C-DHA and ³H-Oleic Acid Tracers

Author： Polozova Alla Salem Norman

Publisher： Humana Press, Inc

ISSN： 0895-8696

Source： Journal of Molecular Neuroscience, Vol.33, Iss.1, 2007-09, pp. : 56-66

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

We conducted a study aimed at a direct comparison of the plasma dynamics and uptake of docosahexaenoic (DHA) and oleic (OA) fatty acids by various organs. ¹⁴C-DHA and ³H-OA were intravenously co-injected into mice. At 5 min after injection, more than 40% of the ¹⁴C-DHA, but less than 20% of the ³H-OA, labels was associated with the liver. Heart uptake of ¹⁴C-DHA was three to four times greater compared to the ³H-OA label. Brain incorporation of ¹⁴C-DHA slowly rose to 0.7% at 24 h, but it remained at the 1–1.5% level for ³H-OA. Total ¹⁴C activity in plasma reached 2% of the injected dose at 20 min and leveled off at 0.5% after 1.5 h. Fifteen percent of ¹⁴C-DHA plasma activity at 30 min was associated with non-esterified fatty acids, whereas about 85% was recovered in triglycerides in very low-density lipoprotein (VLDL) and LDL fractions. Only 30% of ³H-OA derived activity was found in the VLDL fraction at 30 min. All ³H activity in plasma at later time points was in catabolite fractions. These findings demonstrate that liver plays an important role in the initial selectivity for DHA. It is likely that DHA is specifically taken up by liver, esterified, loaded into lipoproteins, and then delivered to brain, heart, and other target tissues.