6-Mercaptopurine (6-MP) is an inhibitor of purine synthesis and interconversion.1 It is rapidly converted to 6-mercaptopurine ribonucleoside-5'-monophosphate, which inhibits phosphoribosyl pyrophosphate (PRPP) amidotransferase, the rate-limiting enzyme in purine synthesis. It also inhibits the conversion of IMP to adenylosuccinic acid and xanthylic acid and blocks AMP formation in vitro. 6-MP (30 mg/kg) inhibits growth of sarcoma 180, adenocarcinoma E 0771, and adenocarcinoma 755 tumors and reduces the size of leukemia L1210 subcutaneous growths in mice.2 It also decreases delayed-type hypersensitivity and thyroid inflammation in a guinea pig model of thyroiditis when administered pre- or post-disease onset.3 Formulations containing mercaptopurine have been used for maintenance therapy in patients with acute lymphoblastic leukemia.4
1.Brockman, R.W.Biochemical aspects of mercaptopurine inhibition and resistanceCancer Res.23(8)1191-1201(1963) 2.Skipper, H.E., Thomson, J.R., Elion, G.B., et al.Observations on the anticancer activity of 6-mercaptopurineCancer Res.14(4)294-298(1954) 3.Spiegelberg, H.L., and Miescher, P.A.The effect of 6-mercaptopurine and aminopterin on experimental immune thyroiditis in guinea pigsJ. Exp. Med.118(5)869-890(1963) 4.Alsous, M., Abu Farha, R., Alefishat, E., et al.Adherence to 6-mercaptopurine in children and adolescents with acute lymphoblastic leukemiaPLoS One12(9)e0183119(2017)
















