title: Transport, utilization and biliary secretion of lysophosphatidylcholine in the rat liver.
abstract: The hepatic uptake, transport and utilization of plasma lysophosphatidylcholine (lysoPC) and its contribution to biliary lipid secretion have been investigated in bile-fistula rats. The animals were given a single intravenous dose of sn-1-[1-14C]palmitoyl-lysoPC, under constant intravenous sodium taurocholate infusion (1 mumol/min), and the fate of the label was followed in blood, bile and liver for up to 3 h. The livers were excised at given time points, extracted and/or homogenized to determine the lipid distribution and subcellular location of radioactivity. LysoPC was rapidly cleared from plasma, though a consistent fraction of the label persisted in plasma over the experimental time-period in the form of either lysoPC or PC. Recovery of radioactivity in the liver varied from 15.6% after 5 min to 19.5% after 3 h. Hepatic lysoPC underwent rapid microsomal acylation to form specific PC molecular species (mainly 16:0-20:4 and, to a lesser extent, 16:0-18:2 and 16:0-16:1). Ultrafiltration, dialysis and gel-chromatographic analyses of cytosolic fractions (post 105,000 X g supernatants) indicated that lysoPC is transported to the site of acylation mostly as a macromolecular aggregate with an approx. Mr of 14,400. Small amounts of radioactivity were secreted into bile over 3 h (20% in the form of lysoPC and the remainder as 16:0-18:2 and 16:0-20:4 PC species). Plasma lysoPC, taken up by the liver, is mostly transported by a cytosolic carrier with a molecular weight close to fatty-acid-binding proteins; it then enters a distinct acylation pathway, selective for some polyunsaturated-PC species and does not contribute significantly to biliary secretion, either directly, or through its products.
authors: II Division of Gastroenterology, University of Rome La Sapienza, Italy.
authors: M
authors: M
authors: Angelico
authors: D
authors: D
authors: Alvaro
authors: R
authors: R
authors: Masella
authors: S
authors: S
authors: Ginanni Corradini
authors: A
authors: A
authors: Cantafora
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism*; D001692:Biological Transport; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000737:chemistry; D008099:Liver / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000737:chemistry
chemical_list: D008244:Lysophosphatidylcholines