Metabolism and Metabolic Effects of 8-Azainosine and 8-Azaadenosine1

8-Aza-Hr,2 synthesized initially by Davoll (12), has antitu mon activity in experimental systems and differs in its me tabolism from such closely related compounds as inosine and 6-thioinosine (10). In a preliminary study of the metabo lism of [3H]-8-aza-HR, we found conversion to phosphates of 8-aza-AR (2). Although 8-aza-AR was synthesized some years ago (12), little is known about its metabolic effects or its metabolism, except for observations that it is a good substrate for adenosine kinase (22) and adenosine deami nase (1). The facts that 8-aza-HR is converted to nucleotides of 8-aza-AR and that 8-aza-AR is readily deaminated raised the possibilities that the biological activity of 8-aza-HR may be due entirely or in part to its conversion to 8-aza-A nucleo tides on that conversely, the biological activity of 8-aza-AR may be due to its conversion to 8-aza-HR. We report here the metabolism and certain metabolic effects of these nu cleosidesin cellcultures.Preliminaryreportsof some of these results have been made (2, 3).