The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagons-likepeptide-1 (GLP-1), are a group of gastrointestinal hormones that cause an increase in the amount ofinsulin released from the beta cells of the islets of Langerhans after ingestion of food.The intestinal peptide GIP was first isolated from porcine upper small intestine. The sequences ofporcine, bovineand human GIP5have been determined, each has 42 amino acids, andthe sequencesis 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 thatGIP belongs to the vasoactiveintestinal peptide (VIP)/Glucagon/secretin family. GIP is agastrointestinal peptide hormone that is released from duodenal endocrine K cells after absorption ofglucose or fat. GIP is a potent releaser of insulin in experimental animalsandin manprovidedthat the blood glucose is above basal level. Plasma level of GIP is elevated after an oral glucose load or ameal in normal man. This increase after a meal is below normal in newly diagnosed insulindependentdiabetics.It is now being recognized that GIP receptor is also expressed in organs and cells such asduodenum, small intestine, pancreatic alpha-cell, adipocyte and osteoblast. These results demonstrateGIP may have a lot of physiological effect in additionto their glucoregulatory effects.GIP is rapidly inactivated by the enzyme dipeptidyl peptidase- 4 (DPP- 4) to GIP (3-42) with a bloodhalf-life of only several minutes. DPP- 4 inhibitor can prolong the half-life of GIP, that expectingtreatment of incretin effect.The kit can be used for measurement of total GIP [both GIP (1-42) and GIP (3-42)] in rat plasma withhigh sensitivity. It will be a specifically useful tool for incretin research.Principle: ThisELISAkit for determination of rat total GIP is based on a sandwich enzyme immunoassay. To thewells of plate coated with highly purified mouse monoclonal antibody against rat GIP, standards orsamples are added for the 1st step immunoreaction. Afterthe1st step incubation and plate washing, HRPlabeled antibody solution against rat GIP is added as the 2nd step to form antibody - antigen - labeledantibody complex on the surface of the wells. After the 2nd step incubation and rinsing out excesslabeled antibody, Finally, HRP enzyme activity is determined by 3,3’,5,5’-Tetramethylbenzidine (TMB)and the concentration of rat total GIP is calculated.Features: This ELISA kit is used for quantitative determination of rat totalGIPin plasma and culture medium supernatant. The kit is characterized by its sensitive quantification and high specificity. In addition, it has no influence by other components in samples. GIP standard is highly purified synthetic product.