Transferrin Receptors in Rat Brain: Neuropeptide-Like Pattern and Relationship to Iron Distribution

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 82; no. 13; pp. 4553 - 4557
• Main Authors: Hill, Joanna M., Ruff, Michael R., Weber, Richard J., Pert, Candace B.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.07.1985; National Acad Sciences
• Subjects: Animals; Antibodies; Antibodies, Monoclonal; Autoradiography; Biochemistry and metabolism; Biological and medical sciences; Brain; Brain Chemistry; Central nervous system; Cerebellar cortex; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Iron - analysis; Male; Monoclonal antibodies; Nerve Tissue Proteins - analysis; Neuroglia; Neurons; Olfactory pathways; Rats; Rats, Inbred Strains; Receptors; Receptors, Cell Surface - analysis; Receptors, Transferrin; Tissue Distribution; Transferrin - metabolism; Transferrin receptors; Transferrins; Vertebrates: nervous system and sense organs; Transferrin; Rat; Rodentia; Central nervous system; Iron; Neuropeptide; Autoradiography; Vertebrata; Mammalia; Animal; Distribution; Comparative study; Biological receptor
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.82.13.4553

We have characterized and visualized the binding of125I-labeled transferrin to sections of rat brain. This saturable, reversible, high-affinity (Kd= 1 × 10-9M) binding site appears indistinguishable from transferrin receptors previously characterized in other tissues. Moreover, a monoclonal antibody raised to rat lymphocyte transferrin receptors could immunoprecipitate recovered intact transferrin solubilized from labeled brain slices, indicating that labeling was to the same molecular entity previously characterized as the transferrin receptor. The pattern of transferrin receptor distribution visualized in brain with both125I-labeled transferrin and an anti-transferrin receptor monoclonal antibody are almost indistinguishable but differ from the pattern of iron distribution. Iron-rich brain areas generally receive neuronal projections from areas with abundant transferrin receptors, suggesting that iron may be transported neuronally. However, many brain areas with a high density of transferrin receptors appear unrelated to iron uptake and neuronal transport and form a receptor distribution pattern similar to that of other known neuropeptides. This ``neuropeptide-like'' distribution pattern suggests that transferrin may have neuromodulatory, perhaps behavioral, function in brain.