Gastric inhibitory polypeptide receptor (GIPR) mediates GIP-induced secretion of insulin by pancreatic islet beta cells after a meal. GIPR is a gastrointestinal peptide hormone of 42 aa that is released from duodenal endocrine K cells after absorption of glucose or fat. Stimulation of the GIPR on pancreatic cells activates adenylyl cyclase and mitogen-activated protein kinase, resulting in increased insulin secretion. Mice with a targeted mutation of GIPR have higher blood glucose levels with impaired initial insulin response after oral glucose load. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804