Gastric inhibitory polypeptide (GIP), also known as the glucose-dependent insulinotropic peptide belongs to the secretin family. GIP is derived from a 153-amino acid proprotein and circulates as a biologically active 42-amino acid peptide. GIP is synthesized by K cells, which are found in the mucosa of the duodenum and the jejunum of the gastrointestinal tract as well as in beta-cells in the pancreas.

GIP has been reported to play a role in neutralizing stomach acid to protect the small intestine from acid damage, reducing the rate at which food is transferred through the stomach, and inhibiting the GI motility and secretion of acid. Recently it has been believed that the function of GIP is to induce insulin secretion, which is primarily stimulated by hyperosmolarity of glucose in the duodenum. In addition, GIP has been reported to have significant effects on fatty acid metabolism through stimulation of lipoprotein lipase activity in adipocytes. GIP release has been demonstrated in the ruminant animal and may play a role in nutrient partitioning in milk production (lipid metabolism).

GIP also has clinical applications. It has been reported that Type 2 diabetics are not responsive to GIP. Additionally, studies with knockout mice suggested that absence of GIP receptors correlates with resistance to obesity.

Standard, Biotinylated Gastric Inhibitory Polypeptide peptide, and Positive Control should be stored at -20°C after arrival. Avoid multiple freeze-thaws. The remaining kit components may be stored at 4°C. Opened Microplate Wells and antibody (Item N) may be stored for up to 1 month at 2° to 8°C. Return unused wells to the pouch containing desiccant pack and reseal along entire edge.