Catecholamine control of enzymes involved in isocitrate oxidation of rat liver mitochondria.

Treatment of rats or liver homogenates with catecholamines (isoproterenol or noradrenaline) increased activities of both NAD+ -dependent isocitrate dehydrogenase and NAD(P)+-transhydrogenase (in the direction of hydrogen transfer NADPH----NAD+) with no change in NADP+ -dependent isocitrate dehydrogenase. These effects were realized via beta-adrenoceptors. Cyclic AMP mimicked the catecholamine action on incubation with liver homogenate. The effects of catecholamines and cyclic AMP were not additive.