Corticosterone (4-pregnen-11, 21-diol-3, 20-dione) is secreted by the adrenal cortices and is the major glucocorticoid found in rats and mice. The level of corticosterone in rats and mice is of the same order of magnitude as that of cortisol in the human, and can be used as an index of adrenal function.
Response can be observed from ACTH release (causing secretion) and by dexamethasone or hypophysectomy (causing suppression). Stress also plays a very important part in the circulating corticosterone levels causing rapid increases under stressful situations including temperature change, experimental stimuli, or unusual routine.
The Corticosterone EIA kit is a competitive enzyme immunoassay utilising a polyclonal corticosterone antibody coated onto the inner surface of polystyrene microtitre wells. Calibrators, controls and diluted samples are incubated with enzyme (horseradish peroxidase) labelled corticosterone in the antibody coated wells overnight at 2-8°C.
The wells are washed and colour is developed using a chromogenic substrate (TMB). The absorbance of the stopped reaction mixtures is read in a microplate plate reader, colour intensity developed being inversely proportional to the concentration of corticosterone.
