IDENTIFICATION AND METABOLIC CLEARANCE OF CORTISOL AND CORTISONE IN A MARINE TELEOST, THE SEA RAVEN HEMITRIPTERUS AMERICANUS GMELIN (FAMILY SCORPAENIDAE)

Abstract

SUMMARY Cortisol and cortisone were identified and their levels determined in sea raven plasma by a double isotope derivative assay involving acetylation with [1- 3 H]acetic anhydride, purification by thin-layer and paper chromatography, followed by recrystallization to constant 3 H: 14 C ratios. The mean level of cortisol in four plasma samples was 7·2±1·0 μg/100 ml (range 4·0–9·2) and the mean level for cortisone in three samples was 1·1 ± 0·2 μg/100 ml (range 0·7–1·5). Metabolic clearance rates (MCR) were determined for both corticosteroids by the method of continuous infusion over an 8-h period. The mean MCR for cortisol in five fish was 126 ± 17 ml/kg/h, and for cortisone 449 ± 48 ml/kg/h in six fish. The mean percentage conversion of [1,2- 3 H]cortisol to cortisone was 9·4 ± 2·9%. There was no evidence of any significant conversion of cortisone to cortisol.