Pyrophosphate-loaded hepatocytes show increased iron uptake from transferrin.

Exogenously added pyrophosphate was found associated with hepatocytes in suspension, particularly in the presence of calcium ions. The cell-associated pyrophosphate was recovered with the stroma fraction. Pyrophosphate thus bound did not affect cellular ATP, leakage of lactate dehydrogenase or trypan blue exclusion. Compared to control cells, pyrophosphate-loaded hepatocytes showed an approximately 70% increase in iron accumulation from transferrin. The excess iron was handled by the pyrophosphate-loaded cells as control cells. The relevance of pyrophosphate to hepatocyte iron uptake is discussed.