Significance of non-esterified fatty acids in iron uptake by intestinal brush-border membrane vesicles.
Iron uptake from Fe/ascorbate by mouse brush-border membrane vesicles is not greatly inhibited by prior treatment with a variety of protein-modification reagents or heat. Non-esterified fatty acid levels in mouse proximal small intestine brush-border membrane vesicles show a close positive correlation with initial Fe uptake rates. Loading of rabbit duodenal brush-border membrane vesicles with oleic acid increases Fe uptake. Depletion of mouse brush-border membrane vesicle fatty acids by incubation with bovine serum albumin reduces Fe uptake. Iron uptake by vesicles from Fe/ascorbate is enhanced in an O2-free atmosphere. Iron uptake from Fe/ascorbate and Fe3+-nitrilotriacetate (Fe3+-NTA) were closely correlated. Incorporation of oleic acid into phosphatidylcholine/cholesterol (4:1) liposomes leads to greatly increased permeability to Yb3+, Tb3+, Fe2+/Fe3+ and Co2+. Ca2+ and Mg2+ are also transported by oleic acid-containing liposomes, but at much lower rates than transition and lanthanide metal ions. Fe3+ transport by various non-esterified fatty acids was highest with unsaturated acids. The maximal transport rate by saturated fatty acids was noted with chain length C14-16. It is suggested that Fe transport can be mediated by formation of Fe3+ (fatty acid)3 complexes.
Simpson
R J
RJ
Division of Clinical Cell Biology, MRC Clinical Research Centre, Harrow, U.K.
Moore
R
R
Peters
T J
TJ
D000818:Animals; D001205:Ascorbic Acid; D001692:Biological Transport; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008081:Liposomes; D008670:Metals; D051379:Mice; D008871:Microvilli / Q000378:metabolism; D009571:Nitrilotriacetic Acid; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D011817:Rabbits
D005230:Fatty Acids, Nonesterified; D008081:Liposomes; D008670:Metals; D009829:Oleic Acids; D019301:Oleic Acid; D007501:Iron; D009571:Nitrilotriacetic Acid; D001205:Ascorbic Acid