COMPARATIVE EFFECTS OF ALDOSTERONE AND HEAT ACCLIMATIZATION ON OXIDATIVE ENZYMES IN RAT TISSUES

Abstract

The activities of several oxidative enzymes of liver, kidney, heart, and muscle tissue were compared in groups of rats treated with aldosterone, exposed to heat stress, and acclimatized to a hot environment. A single intraperitoneal injection of 2 μg D-aldosterone monoacetate/g body weight caused an increase in the activity of liver succinoxidase after 3 h and in kidney and heart succinoxidase after 8 h. Similarly, the activity of cytochrome oxidase was enhanced 8 h after a single injection of the mineralocorticoid. Repeated administration of 2 μg D-aldosterone monoacetate/g body weight for 16 days (chronic aldosterone) elicited a significant decrease (P < 0.05) in liver succinoxidase similar to that in heat stress (P < 0.05) and in acclimatization to a hot environment (P < 0.05). On the other hand, the activity of the succinoxidase of kidney, heart, and muscle tissues was slightly stimulated by the chronic aldosterone treatment, by heat stress, and by heat acclimatization. Although the activity of cytochrome oxidase of the liver and kidney was decreased by the chronic aldosterone treatment, heat stress, and heat acclimatization, there was a slight increase in the activity in that of heart and muscle. Most treatments elicited a marked rise in the activity of kidney xanthine oxidase (P < 0.01), whereas the enzyme activity of liver, heart, and muscle was relatively unaffected.