Absorption and transport of base moieties of phosphatidylcholine and phosphatidylethanolamine in rats.
The absorption and transport of the base moieties of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) which were fed to rats were compared. The major absorption site of ethanolamine-labeled PE was proximal jejunum while choline-labeled PC was absorbed almost equally throughout the jejunum. Lysophospholipids, glycerophosphoryl bases and constituent bases were the main digested products in intestinal content. This shows that base-labeled phospholipids were hydrolyzed to water-soluble products as well as lysophospholipids before absorption. The radioactivities from both phospholipids existed mainly in their parent phospholipids and water-soluble products in the intestinal mucosa. The amounts of lymphatic transport of the radioactivities from choline-labeled PC and ethanolamine-labeled PE were 17% and 8%, respectively, at 8 h after administration. The liver in lymph-cannulated rats contained 23% and 48% radioactivity from PC and PE, respectively, suggesting that base moieties of phospholipids, especially PE, were transported mainly via a non-lymphatic route, probably the portal vein, to the liver, as water-soluble products. The radioactivity from both base-labeled phospholipids in the liver was distributed in the parent phospholipids and water-soluble fractions. Ethanolamine-labeled PE was also incorporated into PC in the liver. These results indicate that intestinal absorption and transport of the base moiety of dietary PC and PE are similar; however, their intestinal absorption site and the extent of their separation during transport between the lymphatic and portal systems differ markedly.
D000818:Animals; D001692:Biological Transport; D002794:Choline / Q000493:pharmacokinetics; D004041:Dietary Fats / Q000378:metabolism; D019856:Ethanolamine; D004983:Ethanolamines / Q000493:pharmacokinetics*; D007408:Intestinal Absorption; D007583:Jejunum / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008208:Lymphatic System / Q000378:metabolism; D010713:Phosphatidylcholines / Q000493:pharmacokinetics*; D010714:Phosphatidylethanolamines / Q000493:pharmacokinetics*; D051381:Rats; D011919:Rats, Inbred Strains
D004041:Dietary Fats; D004983:Ethanolamines; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D019856:Ethanolamine; D002794:Choline