Effect of cimetidine on deoxyribonucleic acid biosynthesis in gastrointestinal mucosa of rats.

Using oxyntic and duodenal rat tissues, we investigated the effects of cimetidine, an antisecretagogue and a H2-receptor antagonist, on deoxyribonucleic acid (DNA) biosynthesis, determined according to the 3H-thymidine incorporation into DNA fraction. Serum gastrin concentration and DNA biosynthesis in the tissues increased significantly in the fed rats, and administration of cimetidine significantly increased both serum gastrin concentration and the DNA biosynthesis in the oxyntic tissues. There was a significant correlation between the oxyntic DNA biosynthesis and the serum gastrin concentration. Cimetidine in concentrations of 0.01 to 1.0 mM, added to the incubation mixture, had no stimulatory effect on the DNA biosynthesis in the oxyntic tissues. These results support the hypothesis that DNA biosynthesis in oxyntic mucosa of rats may be regulated by the circulating gastrin.