EFFECT OF SIMULTANEOUS ADMINISTRATION OF SACCHARIN OR CYCLAMATE AND A NITROSAMIDE (MNU) ON BLADDER EPITHELIUM AND THE DOMINANT LETHAL TEST

Three groups consisting of 150 Swiss male mice per group received orally sodium nitrite and methylurea daily. Two of these groups also received either sodium saccharin (about 3.4 g/kg) or sodium cyclamate (1.9 g/kg) while a fourth group served as control. After one week of this treatment, these animals were twice mated and a significant mutagenic induction (dominant lethals) was observed but this was solely due to the formation in the stomach of N-methylnitrosourea (MNU) from the sodium nitrite and methylurea administered. After further treatment for 90 days, no hyperplastic or neoplastic changes of the bladders were observed. In the lungs of some treated animals microscopic foci of nodular epithelial proliferation were observed but could only be related to the treatment with sodium nitrite and methyl urea. © 1979.