Arginase activity and manganese content in various tissues from control and DOCA salt-hypertensive male Sprague Dawley rats

Mammalian arginase (L-arginine amidinohydrolase, EC 3.5.3.1) catalyzes the hydrolysis of arginine to ornithine plus urea. One general property of arginase is the requirement of bivalent metal ions, particularly manganese, for full activity and structural stabilization of the enzyme. Arginase activity and manganese content were determined in various tissues from male Sprague Dawley rats. The activity of arginase was found to greatly differ between the tested tissues, being liver > > intestine = kidney > brain = heart. The content in manganese followed a similar distribution pattern. Arginase activity and manganese content were also determined in the various tissues ofDOCA salt-treated male Sprague Dawley rats. The treatment affected arginase activity and manganese content in a tissue-dependent manner, both during induction of hypertension (after 3 weeks of treatment) and in fully hypertensive (after 8 weeks of treatment) male Sprague Dawley rats: increased in the intestine, decreased in liver and kidney, arginase activity and manganese content were not affected in brain and heart. The results of the present study suggest that in male Sprague Dawley rats manganese may play a role in the tissue-specific activity of arginase as well as in the regulation of its activity during DOCA salt induction of hypertension.