The role of prostaglandin E_2 (PGE_2) on colon carcinogenesis was studied using indomethacin, PGE_2 synthesis inhibitor, and PGE_2 in male 7 weeks Donryu rats. Rats received intrarectal instillation of n-methyl-n-nitro-n-nitrosoguanidine (MNNG) or methylnitrosourea (MNU). Rats were divided into 7 groups randomly as follows
rat colon carcinogenesis
tissue prostaglandin E_2 content
indomethacin