Might have a transport function across the blood brain barrier. Is supposed to have similar functions as transthyretin which must have evolved after the stage of the amphibians in evolution. Monomer. Found in cerebrospinal fluid. Expressed mainly in choroid plexus. Much lower expression in other brain areas, and absent from liver. Expressed throughout amphibian metamorphosis. Belongs to the calycin superfamily. Lipocalin family.