Determination of dexamethasone and corticosterone half-lives in male broilers

Normal broiler males were used in a series of experiments to determine the rate of disappearance of dexamethasone, a synthetic corticoid, and corticosterone, the quantitatively most important glucocorticoid in the bird. Determination of the half-life (T1/2) of these compounds following an intravenous bolus injection was by high performance liquid chromatography. Half-lives for dexamethasone and corticosterone were found to be 36 and 22 min, respectively. The slower rate of disappearance from the blood may help to explain the ability of dexamethasone to overcome some of the problems associated with hyperthermic stress in birds. This method of quantitating exogenously administered steroids is applicable not only to basic research but also to analyses by inspection and regulatory agencies.