Vomeroglandin, a subform of mouse CRP-ductin, is a protein strongly expressed in the glands of mouse vomeronasal system. Both the proteins contain several of scavenger receptor cysteine-rich and CUB domains and one ZP domain. This domain arrangement is similar to those of rat Ebnerin, human DMBT1, and rabbit hensin, In situ hybridization analysis shows strong expression of vomeroglandin mRNA in the glands of vomeronasal system. Immunological analyses detect both membrane-bound and secreted forms of vomeroglandin, The secreted protein seems to be localized in the lumen of the vomeronasal organ, playing a certain role in the pheromone perception.