6-Methylmercaptopurine: Identification as Metabolite of 6-Mercaptopurine in vivo and Its Activity in vitro

Abstract
1. 6-methylmercaptopurine was identified as a urinary metabolite of 6-mercaptopurine in normal Sprague-Dawley rats. 2. In in vitro experiments, 6-MeMP exerted greater inhibition of both formate and glycine incorporation into the combined nucleic acid and protein fractions of Sarcoma 180 ascites tumor cells than did 6-MP.