Some Metabolic Effects Exerted by Azaserine and Purine Analogs in Vivo.

been elucidated, although metabolic effects induced by these agents employed singly have received considerable study and have been discussed in recent reviews (5, 14, 23, 26, 28, 31, 43, 44). The metabolic alteration deemed re sponsible for the tumor-inhibitory effect of azaserine is the blockade of purine nucleotide biosynthesis de novo. Re cent evidence, however, has suggested that this site of action may be responsible only in part for the synergic in hibition demonstrated by combinations of azaserine and 6chloropurine (38). It has been suggested that various purine analogs con