The determination of plasma corticosterone of chickens by high pressure liquid chromatography

A simple method for separating and measuring chicken plasma corticosterone by high pressure liquid chromatography (HPLC) is described. Plasma was extracted twice, first, with isooctane to remove nonpolar steroids and, second, the polar steroids were extracted with dichloromethane. Analytical recovery of added corticosterone was 96.5 +/- 1.9% (mean +/- SE). Interassay variability was less than 8% (coefficient of variation = 7.7%). The assay was specific for corticosterone with the exception of deoxyhydroxycorticosterone, which we do not believe to be in significant amounts in chicken plasma. Comparison of values obtained by the HPLC method to a radioimmunoassay method revealed no significant differences. Advantages of the present method include high specificity, simplicity, and cost. A disadvantage is the relatively large amount of corticosterone (plasma volume) required for detection. The method should be applicable to corticosterone determinations in the plasma of other species as well.