Effects of NaCl,
Tween 60 and N-ethyl-N'-nitro-N-nitroso-
guanidine (
ENNG) on gastric
carcinogenesis were investigated in male Wistar rats. Animals received a single dose of
N-methyl-N'-nitro-N-nitrosoguanidine (
MNNG) at 250 mg/kg
body weight by gastric tube followed one week later by either 10% NaCl in their diet, twice-weekly applications of 1 ml of saturated NaCl
solution by gastric tube, 1.0%
Tween 60 in their
drinking water or 0.0005%
ENNG in their
drinking water. One group of rats were given
MNNG 24 h after a single application of 1 ml of saturated NaCl
solution to investigate the effect of NaCl on initiation. A single dose of
MNNG to rats resulted in development of multiple epithelial
tumors in the forestomach and no epithelial
tumors in the glandular stomach after 52 weeks. There were no differences in
tumor incidences of the forestomach and glandular stomach between experimental groups which were given a subsequent treatment with NaCl or
Tween 60 and the control group with
MNNG alone.
ENNG significantly enhanced the
tumor induction in the glandular stomach, while
ENNG alone did not induce any
tumors in the stomach. The NaCl treatment prior to
MNNG administration also increased
tumor development in the glandular stomach but not in the forestomach.