A prophylactic or therapeutic method for a disease associated with
decreased expression of AOP-1 gene or AOP-1, comprising (1) transfecting
a nucleic acid encoding AOP-1 or a nucleic acid encoding a polypeptide
having an addition, deletion or substitution of one or more amino acids
as compared with the amino acid sequence of AOP-1 while retaining the
function of AOP-1, or (2) administering a material enhancing the
expression of AOP-1 gene, a material enhancing the production of AOP-1 or
a material enhancing the function of AOP-1.