Enhancement by methylated oxypurines of the frequency of induced chromosomal aberrations

Abstract

Eight methylated oxypurines were tested for their ability to potentiate the chromosome damage produced by thiotepa and maleic hydrazide in bean (Vicia faba) roots and by thiotepa in Chinese hamster cells. Caffeine was the strongest potentiating agent in Vicia faba roots, 8‐chlorocaffeine in Chinese hamster cells. In both materials tetramethyluric acid was the least active of the methylated oxypurines tested. Caffeine, theobromine and theophylline were effective potentiating agents but poor inducers of exchange‐type aberrations in prophase and the post‐synthetic period of interphase. Tetramethyluric acid, in contrast, was a poor potentiating agent but effective inducer of exchange‐type aberrations. In Vicia faba, post‐treatments with caffeine as potentiating agent reduced by a factor of about 4.5 the concentration of thiotepa required to produce a given aberration frequency.