Abstract
The effects of cortisol on components of the liver microsomal mixed function oxidase system (MFO) of immature and starved rainbow trout, Salmo gairdnerii, Rich., were studied 3, 7 and 21 days after intraperitoneal implantation of cortisol-containing cholesterol pellets. The treatment resulted in significantly elevated NADPH cytochrome c reductase activities, concomitant with elevated plasma cortisol levels, at all sampling events, while no significant effects on either liver cytochrome P-450 or microsomal protein contents was observed. The cortisol-treated fish lost considerably more body weight than corresponding controls during the experimental period, while the effects on liver wet weight and liver somatic index were inconclusive.