CORTISOL DOES NOT AFFECT HEPATIC ALPHA-ADRENOCEPTOR AND BETA-ADRENOCEPTOR PROPERTIES IN RAINBOW-TROUT (ONCORHYNCHUS-MYKISS)

Distribution and function of hepatic alpha- and beta-adrenoceptors wer e examined in rainbow trout (Oncorhynchus mykiss) injected with slow r elease hydrogenated coconut oil implants alone (sham) or containing co rtisol. a- and P-Adrenoceptors were assayed on purified hepatic membra nes 10-14 days post-implantation using H-3-prazosin (alpha) and H-3-CG P (beta). At 10-14 days, plasma cortisol values were significantly ele vated to approximately 220 compared with 35.0 ng ml(-1) in cortisol im planted vs, sham trout. No significant differences were found between any of the experimental groups for either the affinity (K-d) or maxima l number of binding sites (B-max) for either receptor type.Epinephrine significantly stimulated glucose release from hepatocytes isolated fr om sham injected trout, but not from cortisol-treated fish. Epinephrin e-induced glucose release was blocked by both alpha- and beta-antagoni sts. These studies do not support the hypothesis that rainbow trout ex posed to chronic cortisol alter properties of hepatic adrenoceptors.