A specific receptor for retinol binding protein as detected by the binding of human and bovine retinol binding protein to pigment epithelial cells.

By means of autoradiographic techniques the specific plasma carrier of retinol, namely retinol binding protein (RBP) in a radioactive form (retinol-125I.RBP), bound specifically in vivo to the choroidal surface of intact, isolated bovine pigment epithelial cells. The retinol-125I.RBP did not bind to the retinal surface of the pigment epithelial cells nor did not bind to photoreceptors. Retinol is normally provided to the retina from the blood via a specific complex formation with a receptor on the chordial surface of the pigment epithelial cells. Retinol metabolism might be deranged in some diseases through a defect in the pigment epithelial receptor for RBP.