Abstract
Summary
Hamsters having or not surgically implanted intracholecystic cholesterol pellets were given carcinogen diethylnitrosamine (DEN) or dimethylnitrosamine (DMN), dissolved in drinking water. Exposure to these carcinogens lasted from 8 to 22 weeks. No gallbladder tumors were found in DEN-treated hamsters, having or not intracholecystic “experimental stones.” In 68% of hamsters exposed to DMN and having gallbladder pellets, adenocarcinomas were found. Only one gallbladder tumor was detected in DMN-treated animals who had no gallbladder pellet. It was concluded that “experimental gallbladder stone” enhanced the malignant transformation of gallbladder mucosa in DMN-treated hamsters. It was considered probable that dysplasia of bile duct and gallbladder epithelium observed only in DMN-treated animals represents a premalignant lesion. Presence of this premalignant lesion associated with nonspecific irritation of gallbladder mucosa by a “stone” may be considered an important etiological factor contributing to gallbladder malignancy in hamsters.
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