Endocytosis and degradation of bovine apo- and holo-lactoferrin by isolated rat hepatocytes are mediated by recycling calcium-dependent binding sites.

We characterized endocytosis of iron-saturated (holo) and iron-depleted (apo) 125I-labeled bovine lactoferrin (Lf) by isolated rat hepatocytes. Hepatocytes ingested both Lf forms--determined by EGTA/dextran sulfate removal of surface-bound Lf--at maximal endocytic rates of 1.85 and 1.