Adipsin is a serine protease secreted by adipose tissue, and it has also been found in monocytes/macrophages. Adipsin has been identified to be similar to complement Factor D. Adipsin cleaved complement Factor B when the later form complexed with activated complement component C3. Low level expression of Adipsin has been linked to obesity in mouse model sμggesting that defects in Adipsin is the result of this systemic disorder.