[Transferrin receptor and iron deposition pattern in the hepatic lobules of the iron-deficient and iron-overloaded rats].

Wistar rats were made iron deficient by a low iron regimen. Iron overload was produced by repeated intraperitoneal injections of ferric nitrilotriacetate (Fe(3+)-NTA) for one to four months. Hepatic tissues from these iron deficient, overloaded and control rats were examined for transferrin receptor (TfR), transferrin (Tf) and iron after immunohistochemical staining. TfR and Tf were mainly distributed in the peripheral part of the lobule (zone 1) in the normal, iron deficient and iron-overloaded rats. The staining intensity decreased from zone 1 to zone 3. The staining intensity of TfR was strongest in iron-deficiency rat hepatic cells, weakest in iron-overloaded rat hepatic cells when compared with controls. The difference of Tf staining between the three groups of rats was similar to that of TfR. In the iron-overloaded rats, the staining intensity of iron was stronger in zone 1 than in zone 2 and 3, similar to the distribution pattern of TfR and Tf. These findings suggest that (1) iron uptake in hepatic cells in vivo is regulated and mediated by TfR and Tf, (2) the expression pattern of TfR and Tf in zone 1 to zone 3 liver cells may result in the progressive decrease of iron deposition in the hepatic lobules of the iron overloaded rats.