This gene encodes a small peptide hormone that is secreted by cells of the small intestine to regulate gastrointestinal contractions and motility. Proteolytic processing of the secreted protein produces the mature peptide and a byproduct referred to as motilin-associated peptide (MAP). Three transcript variants encoding different preproprotein isoforms but the same mature peptide have been found for this gene. [provided by RefSeq, May 2010].