GIP, a member in the incretin family, secreted from intestinal epithelial K cells, regulates glucose and lipid metabolism by means of binding to GIP receptors. Presented the broad tissue distribution of GIPR, It's not at all surprising that GIP steps have been documented on many tissues apart from tummy, islets, https://www.google.com/maps/d/u/0/edit?mid=10dO8m1HL2Q7Xg0UHUvDuZb09r_rHftg&usp=sharing