Interphotoreceptor retinoid-binding protein in retinal rod cells and pineal gland

Immunoelectron microscopic staining demonstrates Interphotoreceptor Retinoid-Binding Protein (IRBP) in monkey rod cell cytoplasm with virtually none in cone cells. The pineal also contains significant amounts of IRBP demonstrating a similarity of pinealocytes to rod but not cone photoreceptors.