Promotional effect of sodium barbiturate on intestinal tumors induced in rats by dimethylhydrazine.

Noninbred Sprague-Dawley rats were administered 1,2-dimethylhydrazine hydrochloride (DMH) by gavage or methylazoxymethanol acetate by sc inoculation. Thereafter, one group was given water to which 0.1% sodium barbiturate was added, and the other was given drug-free water. They were examined 20 weeks after onset of the experiments. A direct relationship was noted between dosage of DMH and numbers of intestinal tumors induced in the rats. The rats provided with sodium barbiturate-supplemented water developed more intestinal tumors than did those that drank drug-free water.