Effect of Ammonium Chloride on Incidence of Bladder Tumors Induced by 4-Ethylsulfonylnaphthalene-1-Sulfonamide

Abstract

Treatment of female (IF × C57)F1 mice with 4-ethylsulfonylnaphthalene-1-sulfonamide (ENS) produced an alkaline urine associated with the formation of calculi in the bladder and with hydronephrosis. Extensive epithelial hyperplasia and, in some mice, tumors were noted in the bladders. If, however, the urine was made acid through the addition of ammonium chloride (NH4Cl) to the drinking water, neither calculi nor tumors of the bladder were present, though a mild epithelial hyperplasia persisted. Mice treated with NH4CI alone and untreated controls had no histopathologic changes. Physical injury by calculi and/or elevated pH of the urine induced by ENS are essential for bladder tumors to develop. A thorough examination for bladder calculi is necessary for assessment of the environmental significance of bladder tumors in rodents.