Abstract
The effect of N mustard on the incorporation of C*4-formate and Nl5_adenine into the bases of PNA and DNA of small intestine and into the bases of PNA of liver of the rat has been investigated. The drug decreased the incorporation of both precursors into adenine of DNA of intestine to approx. the same extent. This suggests that the drug does not affect specifically the synthesis of the purine skeleton. The drug led to a marked decrease of isotope levels in the bases of DNA of small intestine, but little or no change in the levels in PNA bases of both small intestine and liver.