Further observations on the inhibition of tumor growth by Corynebacterium parvum with cyclophosphamide. III. Effect of C. parvum on cyclophosphamide metabolism.

Results of investigations employing [14C]cyclophosphamide (CY) demonstrated that even though total plasma radioactivity was similar in female C3HeB/FeJ mice treated either with CY alone or Corynebacterium parvum and CY, the proportion of total activity due to nonmetabolized CY was greater when C. parvum was used. These findings indicated that the antitumor effect of C. parvum may not have been entirely due to its immunopotentiating properties but may also have been related to its effect on the metabolism of CY.