In MDCK cells, choline uptake, the first step in the CDP-choline pathway for the biosynthesis of choline-containing phospholipids and osmolytes, occurs via both a transport system highly specific for choline and a non-specific pathway. The specific choline carrier is present at the apical domain of cells grown on dishes and is sodium-independent. Growing the cells on a permeant support results ...

Erythrocytes from lithium treated patients were separated according to the time they had been circulating in the plasma. Choline transport and choline content were measured in the erythrocyte fractions separated according to age, in order to investigate the relationship between decreased choline transport and increased choline content seen in lithium treated patients. The most recently formed e...

In six normal subjects we investigated the effects of oral phosphatidylcholine (lecithin) on the concentrations of plasma choline, erythrocyte choline, and choline-containing lipids. Plasma choline levels rose 1 hr after treatment and remained elevated for 8 hr, with peaks at 3 and 4 hr after phosphatidylcholine. Erythrocyte choline levels also rose, although the rise was slightly delayed relat...

In this study, we examined the molecular and functional characterization of choline transporter in human brain microvascular endothelial cells (hBMECs). Choline uptake into hBMECs was a saturable process that was mediated by a Na(+)-independent, membrane potential and pH-dependent transport system. The cells have two different [(3)H]choline transport systems with Km values of 35.0 ± 4.9 μM and ...

The neonatal mammal requires especially large amounts of choline to sustain growth. Much of this choline is derived from the newborn's only source of food, milk. The concentration of choline in rat milk [182 +/- 24 microM (S.E.M.)] was much higher than that in maternal serum (11.6 +/- 0.9 microM), suggesting that a mechanism capable of concentrating choline into milk must exist. We characterize...

Choline is an essential nutrient for all living cells and is produced extracellularly by sequential degradation of phosphatidylcholine (PC). However, little is known about how choline is produced extracellularly. Here, we report that ENPP6, a choline-specific phosphodiesterase, hydrolyzes glycerophosphocholine (GPC), a degradation product of PC, as a physiological substrate and participates in ...

The capacity of the high-affinity choline transporter (CHT) to import choline into presynaptic terminals is essential for acetylcholine synthesis. Ceramic-based microelectrodes, coated at recording sites with choline oxidase to detect extracellular choline concentration changes, were attached to multibarrel glass micropipettes and implanted into the rat frontoparietal cortex. Pressure ejections...

Choline plays a central role in many physiological pathways, including neurotransmitter synthesis (acetylcholine), cell-membrane signaling (phospholipids), lipid transport (lipoproteins), and methyl-group metabolism (homocysteine reduction). Endurance exercise might stress several of these pathways, increasing the demand for choline as a metabolic substrate. This review examines the current lit...

In contrast with results on the rat, in the rabbit no arteriovenous differences were found in the plasma concentrations of free choline, phosphatidylcholine and lysophosphatidylcholine. The phospholipid values agreed with those of Nelson (1967). Blood samples were taken at intervals and the blood volume was replaced by infusing a dextran solution in which blood cells from earlier samplings were...

Single nucleotide polymorphisms (SNPs) in choline metabolizing genes are associated with disease risk and greater susceptibility to organ dysfunction under conditions of dietary choline restriction. However, the underlying metabolic signatures of these variants are not well characterized and it is unknown whether genotypic differences persist at recommended choline intakes. Thus, we sought to d...