Unlock Exclusive Discounts & Flash Sales! Click Here to Join the Deals on Every Wednesday!
The intestinal peptide GIP was first isolated from porcine upper small intestine. The sequences of porcine, bovine and human GIP have been determined, each has 42 amino acids, and the sequences is highly conserved. The porcine and bovine peptides differ from the human at two and three site, respectively. Takeda et al. have isolated a human cDNA encoding the GIP precursor and confirming that GIP belongs to the vasoactive intestinal peptide (VIP)/Glucagon/secretin family. GIP is a gastrointestinal peptide hormone that is released from duodenal endocrine K cells after absorption of glucose or fat. GIP is a potent releaser of insulin in experimental animals and in man provided that the blood glucose is above basal level. Plasma level of GIP is elevated after an oral glucose load or a meal in normal man. This increase after a meal is below normal in newly diagnosed insulin–dependent diabetics. It is now being recognized that GIP receptor is also expressed in organs and cells such as duodenum, small intestine, pancreatic alpha-cell, adipocyte and osteoblast.