High-performance liquid chromatography of corticosteroids in vertebrate plasma: assay of cortisol in mullet and corticosterone in the rat.

Plasma corticosteroids of eighteen vertebrate species were separated by reversed-phase high-performance liquid chromatography (HPLC). The major corticosteroids identified in these species by HPLC agreed with previous reports which used vigorous criteria for identification. The HPLC technique was validated for the assay of cortisol in mullet plasma and corticosterone in the rat. Qualitative as well as quantitative changes in corticosteroid secretion were detected by HPLC in several vertebrates during exposure to stress.