The ingestion and digestion of human lactoferrin by mouse peritoneal macrophages and the transfer of its iron into ferritin.
Human lactoferrin (Lf) labeled with 125I and/or 59Fe was found to be ingested in vitro by mouse peritoneal macrophages (MPM). The uptake measured after 15 h incubation reached a saturation point at a concentration of 200 microgram/ml in the culture medium, whatever was the iron content of Lf. In such conditions, the uptake of transferrin (Tf) used as a control was 10 times lower. At a concentration of 80 microgram/ml in the medium, one cell picked up about 0.7 X 10(6) molecules of Lf per hour, and 0.13 X 10(6) molecules of Tf per hour. Iron-saturated Lf disappeared from MPM with a half life of 14.5 h, whereas the halflife of iron-free Lf was 4.2 h. Concomitant with the intracellular digestion of Lf, the iron was transmitted to ferritin. These data provide additional support for the hypothesis that Lf plays a key role in iron turnover, especially at the level of the reticuloendothelial system where iron is recovered from the catabolism of erythrocytes.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003911:Dextrans / Q000494:pharmacology; D005293:Ferritins / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D007781:Lactoferrin / Q000276:immunology* / Q000378:metabolism; D007782:Lactoglobulins / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D010873:Pinocytosis; D014168:Transferrin / Q000276:immunology*
D003911:Dextrans; D007782:Lactoglobulins; D014168:Transferrin; D005293:Ferritins; D007501:Iron; D007781:Lactoferrin