Phosphatidylcholine is the major phospholipid in eukaryotic cells. It serves as a structural component of cell membranes and a reservoir of several lipid messengers. Recent studies in yeast and mammalian systems have revealed interrelationships between the two pathways of phosphatidylcholine metabolism, and between these pathways and those for CTP synthesis and secretion via the Golgi. These pr...

The HL-60 leukemia cell line derived from a human acute promyelocytic leukemia is stimulated to differentiate into macrophages within 24-48 hr after exposure to the phorbol ester. 1 2-O-tetradecanoylphorbol-1 3-acetate (TPA). We studied early alterations (within 90 mm of exposure to TPA) in phosphatidylcholine metabolism in HL-60 cells and found that phosphatidylcholine synthesis by methylation...

The regulation of apoB synthesis and secretion by lipids present within bile was investigated in CaCo-2 cells grown on semipermeable filters. Bile acids decreased the basolateral secretion of immunoreactive apoB. Taurocholic acid decreased the secretion of newly synthesized apoB by increasing the rate of apoB degradation, but had no effect on the synthesis and secretion of apoA-I or trichloroac...

The relative degradation of the various molecular species of [3H]phosphatidylcholine in response to thrombin was studied in human platelets following prelabeling with [3H]glycerol and compared to results obtained following labeling with [14C]oleic, [14C]linoleic, or [14C]arachidonic acids. This was of interest since previous work using radioactive fatty acids had led to the conclusion that the ...

BACKGROUND In patients with acute respiratory distress syndrome (ARDS), it is well known that only part of the lungs is aerated and surfactant function is impaired, but the extent of lung damage and changes in surfactant turnover remain unclear. The objective of the study was to evaluate surfactant disaturated-phosphatidylcholine turnover in patients with ARDS using stable isotopes. METHODS W...

Mass spectra have been obtained on molecular species of intact diacyl phosphatidylcholine by means of ammonia gas-induced chemical ionization. MH(+) ions were observed with all species, and other prominent ions in the spectra identified the fatty acid composition. Spectra of phosphatidylcholine containing deuterated methyl groups and spectra obtained using [(15)N]ammonia have allowed identifica...

Membranes of blood cells have an asymmetric bilayer distribution of phospholipid classes. In both erythrocytes and platelet plasma membranes the choline containing phospholipids (sphingomyelin and phosphatidylcholine) are preferentially located in the outer half of the membrane, whereas a large fraction of phosphatidylethanolamine and nearly all phosphatidylserine are confined to the cytoplasmi...

1. The cholesterol content, proportions of different phospholipids and fatty acid components of phosphatidylcholine and phosphatidylethanolamine were studied in rat liver endoplasmic-reticulum membrane, after a single injection of 20-methylcholanthrene or injections of phenobarbitone for 5 days. 2. A marked decrease in the proportion of cholesterol occurred 5 days after injection of 20-methylch...