Eros, S.K. & Milligan, C.L. (1996). The effect of cortisol on recovery from exhaustive exercise in rainbow trout (Oncorhynchus mykiss): Potential mechanisms of action. Physiological Zoology. 69 (5) 1196-1214.
The effects of cortisol on metabolic recovery from exhaustive exercise in rainbow trout (Oncorhynchus mykiss) and potential mechanisms of action were investigated. When the postexercise rise in cortisol is prevented in fish by blocking either cortisol synthesis with metyrapone or cortisol release with dexamethasone, there is a faster recovery of blood and muscle metabolites and acid-base status in those fish than in control fish. To investigate whether preventing the rise in plasma cortisol is responsible for these effects, two experiments were done. Cortisol infused into fish treated with metyrapone returned the rate of recovery to that of control fish. Treatment with 11-deoxycortisol or deoxycorticosterone, intermediates in the cortisol biosynthetic pathway, the levels of which are possibly increased by metyrapone treatment, did not increase the rate of recovery; indeed, plasma cortisol was elevated and recovery prolonged in fish treated with 11-deoxycortisol. These experiments indicate that preventing the postexercise rise in plasma cortisol is associated with decreasing the time required for metabolic and acid-base recovery. The mechanism of cortisol action is not alteration of net acid excretion at the gills or mediated by some action at the RU486-sensitive cortisol receptor. It is suggested that cortisol may play an adaptive role in recovery from exhaustive exercise by providing lactate as a postexercise aerobic fuel.