RELM-beta （Resistin-Like Molecule-beta） is a member of a recently identified family of secreted proteins containing a conserved cystein-rich C-terminus. The RELM family consists of resistin （also called FIZZ3），RELM-alfa （FIZZ1），RELM-beta （FIZZ2） and RELM-gamma. Only resisistin and RELM-beta were found in humans whereas all four RELM family members were identified in rodents.
RELM-beta appears to be produced as a homodimer exclusively by intestinal goblet cells and can be found in high quantities in stool. Remarkably，stool of germ-free mice displaying sterile intestinal tract does not contain RELM-beta until bacterial colonization takes place after pathogen-free mice entered natural environment. Some，but not all，colon carcinoma cell lines secrete RELM-beta into the cell culture supernatant.
