EFFECT OF PHENACETIN AND CAFFEINE ON URINARY-BLADDER OF RATS TREATED WITH N-BUTYL-N-(4-HYDROXYBUTYL)NITROSAMINE

Abstract

The effect of phenacetin and caffeine on urinary bladder carcinogenesis in rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) was examined. Animals were given a high or low dose of BBN for 4 wk and phenacetin or caffeine was administered for 30 or 32 wk, respectively. All animals were examined histologically after 36 wk. The incidence of papillary or nodular hyperplasia, papilloma and cancer of the urinary bladder was significantly higher in groups treated with BBN and then phenacetin than in those treated with BBN alone, especially with a high dose of BBN. Simple hyperplasia and papillary or nodular hyperplasia developed in the urinary bladder of rats treated with phenacetin alone. Papillary proliferative growth of the renal pelvis was seen in 1 rat treated with a low dose of BBN and phenacetin. Treatment with the caffeine after BBN had no enhancing effect and caffeine alone caused no remarkable changes.