Anti-insulin like 4 antibodies are used in the immunodetection of the protein encoded by the INSL4 gene. In humans, the canonical protein has a reported length of 139 amino acid residues and a mass of 15.4 kDa. It is known to be a secreted protein. It is reported to be expressed in placenta, uterus and in fetal perichondrium. A member of the Insulin protein family, it is believed to play an important role in trophoblast development and in the regulation of bone formation. Other names for this target antigen include PLACENTIN, early placenta insulin-like peptide, early placenta insulin-like peptide (EPIL), insulin-like 4 (placenta), insulin-like peptide 4, and EPIL.