抄録
L-cysteine monohydrochloride (LCM) was added to the drinking water of groups of 50 male and 50 female F344/DuCrj rats at levels of 0.5 and 0.25% for 108 weeks. There were no statistically significant differences between treated and control rats in the results of the urine and serum analyses or hematological determinations or in the incidences of tumors, apart from mammary, pituitary and peritoneal lesions. The mammary gland in the females and the pituitary adenoma in males showed some increase in tumor development over the concurrent controls but these values did not differ significantly from the reported spontaneous incidences in this strain. Mesotheliomas were found in 3 of 41 male rats treated with 0.5% LCM but this was again in line with historical control data. It was concluded that LCM does not induce any neoplasms when given orally to F344/DuCrj for 108 weeks.
With regard to non-neoplastic lesions, necrosis of renal papillae was seen in six of 38 females rats in the 0.5% group and 2 of 43 in the 0.25% group. Pelvic hyperplasia was also evident in single female of the two treatment groups. These results suggest that development of papillary necrosis of the urinary tract may occur due to a direct or indirect-action of LCM.
