In vivo and in vitro anti-tumour activity of dimaprit

Dimaprit, a histamine H2-receptor agonist, injected daily i.p. to fibrosarcoma-bearing mice, induced a decrease in tumour growth and an increase in survival. Dimaprit, added to tumour cell cultures (10(-4) M), inhibited the incorporation of 3H-thymidine while embryonic cell cultures were unaffected. This particular anti-tumour activity is probably H2-independent as histamine and impromidine have no effect on tumour cell cultures.