Inhibitory effect of 1α-hydroxyvitamin D3 on N-methyl-N′-nitro-N-nitrosoguanidine-induced gastrointestinal carcinogenesis in Wistar rats

The effect of 1 alpha-hydroxyvitamin D-3 (1 alpha(OH)D-3) on gastrointestinal carcinogenesis induced by N-methyl-N'-nitro-N-nitro-soguanidine (MNNG) was investigated in male Wistar rats. After oral treatment with 0.01% MNNG for 24 weeks, rats were given 0.04 mu g of 1 alpha((OH)D-3 or its vehicle by gastric intubation three times a week for 24 weeks. The incidence of gastric intestinal tumors was 16/30 (53%) in rats treated with MNNG alone, 16/30 (53%) in those treated with MNNG plus vehicle and 8/30 (27%, P < 0.05) in those treated with MNNG plus 1 alpha(OH)D-3. The number of tumors per rat in the group treated with MNNG plus 1 alpha((OH)D-3 was half those in the control groups (P < 0.05). Results indicated that a non-hypercalcemic dose of 1 alpha(OH)D-3 had an inhibitory effect on MNNG-induced duodeno-intestinal carcinogenesis. (C) 1998 Elsevier Science Ireland Ltd.