Differential kinetics of plasma D9-PC in response to D9-choline supplements
Administration of water-soluble D9-choline compounds resulted in an increase of plasma D9-PC that showed uniform peak concentrations at 24-33 h, and a plasma half-life of 2-3d as previously demonstrated after both enteral and parenteral D9-choline chloride administration [Such fatty acid specificity is consistent with the PC synthesis de novo by adult liver, and contrasts to the preferential synthesis of C22:6-PC and C20:4-PC synthesis by the PEMT pathway using betaine as a methyl donor [Importantly, assimilation of D9-POPC resulted in an earlier (9 h) and twofold higher peak concentration of D9-PC without plateau and an increased AUC. This indicates that (D9-)choline assimilation from (D9-PO)PC is faster with respect to plasma (D9-)PC increase, suggesting preferential use of ingested (D9-PO)PC for the (D9-)PC moiety of chylomicrons (see above). The similarly rapid decrease of D9-PC after D9-POPC and other compounds, reaching similarly low levels at 72 h (see Fig. 