Sprague-Dawley系ラットの自然発生腫瘍について

抄録

The spontaneous tumors in Sprague-Dawley rats were studied in 510 females and 450 males which have been used as control groups of various chronic toxicity tests. The incidence of spontaneous tumor was 86.9% in males and 96.0% in females, respectively. In female rats, the most frequent tumor was pituitary adenoma, and followed by breast tumor, insuloma, and adreno-cortical adenoma. In contrast, pituitary adenoma, insuloma, adrenal pheochromocytoma, and hepatic tumor were common tumors in males. The incidence of pituitary adenoma, mammary tumor, thymoma, and adrenocortical adenoma was higher in females than males. On the other hand, the incidence of lung tumor, hepatocellular carcinoma, follicular cell adenoma of the thyroid, pheochromocytoma, and renal tumor was higher in males. Leukemia was also noted about 2.3% in males and 0.8% in females, and all of them were myelogenic leukemia. Moreover, various other tumors were found in other organs or tissues, but their incidences were low.