OB protein binds specifically to the choroid plexus of mice and rats

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 93; no. 11; pp. 5668 - 5673
• Main Authors: Devos, R. (Roche Research Gent, Gent, Belgium.), Richards, J.G, Campfield, L.A, Tartaglia, L.A, Guisez, Y, Heyden, J. van der, Travernier, J, Plaetinck, G, Burn, P
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 28.05.1996; National Acad Sciences; National Academy of Sciences
• Subjects: Adipose tissues; Alkaline Phosphatase - metabolism; Animals; Autoradiography; Binding Sites; Biochemistry; Body weight; Brain - metabolism; CHIMIE; Choroid plexus; Choroid Plexus - metabolism; Food intake; Genes; Genetic mutation; HORMONAS; HORMONE; Iodine Radioisotopes; Leptin; MENINGE; MENINGES; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Obesity - metabolism; Organ Specificity; PEPTIDE; PEPTIDOS; Proteins; Proteins - metabolism; QUIMICA; RADIOGRAFIA; RADIOGRAPHIE; RAT; RATA; RATON; Rats; Rats, Zucker; RECEPTEUR D'HORMONE; RECEPTORES DE HORMONAS; Receptors; Recombinant Fusion Proteins - metabolism; Recombinant Proteins - metabolism; Rodents; SOBREPESO; SOURIS; SURPOIDS; TECHNIQUE DES TRACEURS; TECNICAS DE TRAZADORES; Tritium
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.11.5668

Binding studies were conducted to identify the anatomical location of brain target sites for OB protein, the ob gene product. 125I-labeled recombinant mouse OB protein or alkaline phosphatase-OB fusion proteins were used for in vitro and in vivo binding studies. Coronal brain sections or fresh tissue from lean, obese ob/ob, and obese db/db mice as well as lean and obese Zucker rats were probed to identify potential central OB protein-binding sites. We report here that recombinant OB protein binds specifically to the choroid plexus. The binding of OB protein (either radiolabeled or the alkaline phosphatase-OB fusion protein) and its displacement by unlabeled OB protein was similar in lean, obese ob/ob, and obese db/db mice as well as lean and obese Zucker rats. These findings suggest that OB protein binds with high affinity to a specific receptor in the choroid plexus. After binding to the choroid plexus receptor, OB protein may then be transported across the blood-brain barrier into the cerebrospinal fluid. Alternatively, binding of OB protein to a specific receptor in the choroid plexus may activate afferent neural inputs to the neural network that regulates feeding behavior and energy balance or may result in the clearance or degradation of OB protein. The identification of the choroid plexus as a brain binding site for OB protein will provide the basis for the construction of expression libraries and facilitate the rapid cloning of the choroid plexus OB receptor.