Description
Description: This assay employs a two-site sandwich ELISA to quantitate INS in samples. An antibody specific for INS has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any INS present is bound by the immobilized antibody. After removing any unbound substances, a biotin-conjugated antibody specific for INS is added to the wells. After washing, Streptavidin conjugated Horseradish Peroxidase (HRP) is added to the wells. Following a wash to remove any unbound avidin-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of INS bound in the initial step. The color development is stopped and the intensity of the color is measured.
Overview: Insulin is a polypeptide hormone originating in the beta cells of the pancreas and serving as a principal regulator for the storage and production of carbohydrates. Its secretion is normally stimulated by increases in the amount of glucose in circulation. This leads to higher insulin levels and more rapid tissueassimilation of glucose followed by a decline in the insulin level as the glucose level subsides. In a number of conditions, notably insulinoma and diabetes, this relationship is impaired. Insulin tends to circulate at inappropriately high levels in patients with insulin-secreting pancreatic tumors; such tumors can thus be a cause of hypoglycemia. Accordingly, insulin immunoassays used sometimes in connection with provocative doses of tolbutamide or calcium play an essential role in the identification (and localization) of insulinomas