Insulin-like 3 is a protein that in humans is encoded by the INSL3 gene. It is a secreted protein that belongs to the insulin family. It is expressed in prenatal and postnatal Leydig cells and found as well in the corpus luteum, trophoblast, fetal membranes and breast. It may act as a hormone to regulate growth and differentiation of gubernaculum, and thus mediating intra-abdominal testicular descent.It is a ligand for LGR8 receptor.