Adrenal corticosteroid effects upon rat brain mitochondrial metabolism.

Abstract

Mitochondria from the brains of adrenalectomized rats treated with cortisol 1 hr prior to sacrifice showed a significant increase over controls in state 3 respiration, respiratory control ratio and ADP:O ratio with NAD-linked substrates. A succinate-supported system showed decreased state 3 respiration and respiratory control ratio after cortisol administration. Cycloheximide and actinomycin D alone had no effect on these parameters, but abolished the cortisol induced changes. NADH oxidase activity under hypoxia was higher in mitochondria from intact than from adrenalectomized rats. The rotenone sensitive factor of the NADH dehydrogenase complex was increased by cortisol treatment. The cytochrome content of the mitochondrial respiratory chain was not altered by corticosteroids, suggesting that the corticosteroid-induced increases in mitochondrial state 3 respiration and respiratory control ratio are due to an increased concentration of the rotenone-sensitive factor of the NADH dehydrogenase complex. (Endo...