Simultaneous Determination of Plasma Cortisol by High Pressure Liquid Chromatography and Radioimmunoassay Methods in Fish

The aim of the study was to compare the sensitivity of High Performance Liquid Chromatography (HPLC) and Radioimmunoassay (RIA) analytical methods in the determination of blood plasma cortisol level of common carp (Cyprinus carpio L.). Cortisol, the most potent glucocorticoid, is widely used as an indicator of stress. The monitoring of plasma cortisol concentration was performed during the test focused on stress response caused by handling and long-distance transport of common carp. The samples were collected before, during and after transport. The correlation between blood cortisol level in fish measured by HPLC and RIA was determined using 66 samples. The correlation was HPLC = 0.9454 RIA + 0.40676 and correlation coefficient was 0.815. From the presented results it can be concluded that both methods (RIA and HPLC) can be used for the determination of plasma (serum) cortisol level.