title: Improved method for the determination of the cortisol production rate using high-performance liquid chromatography and liquid scintillation counting.
abstract: Two new methods for the determination of the cortisol production rate using reversed-phase high-performance liquid chromatography are described. One uses ultraviolet detection at 205 nm, the other on-line post-column derivatization with benzamidine, followed by fluorimetric detection. The specific activity of tetrahydrocortisol and tetrahydrocortisone in urine from patients who had received tritium-labelled cortisol was determined by the indicated methods, followed by fraction collection and liquid scintillation counting. The post-column reaction detection procedure was superior to ultraviolet detection, both in selectivity and analysis time. Intra- and inter-assay variance of the post-column reaction detection procedure were 3.7 and 4.7%, respectively. A good correlation (r = 0.99) was obtained between values determined by this procedure and by a thin-layer chromatographic procedure.
authors.affiliation: Department of Clinical Chemistry, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: H E
authors.initials: HE
authors.lastname: van Ingen
authors.forename: E
authors.initials: E
authors.lastname: Endert
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D006801:Humans; D006854:Hydrocortisone / Q000652:urine*; D013056:Spectrophotometry, Ultraviolet; D013760:Tetrahydrocortisol / Q000652:urine; D013761:Tetrahydrocortisone / Q000652:urine
chemical_list: D013761:Tetrahydrocortisone; D013760:Tetrahydrocortisol; D006854:Hydrocortisone