GIP is undoubtedly an incretin that's secreted during the proximal tiny intestine from the existence of nutrients during the intestine. GIP was first named gastric inhibitory peptide since it was believed to lower gastric acid secretion; on the other hand, later experiments shown that its principal influence is stimulating insulin https://docs.google.com/document/d/1bSE0RrndKmZ6FYu0PotYIXkNFnWcw7rtv4s8CcblqWU/edit?usp=sharing