Kitagawa T, Nomura K, Sasaki S
Cancer Res. 1985 Dec;45(12 Pt 1):6078-82.
The potential of X-rays to induce preneoplastic lesions in the rat liver was studied in order to clarify the reason why X-rays are ineffective in inducing hepatocellular carcinoma in this animal. Male newborn rats at 8 or 22 days of age received whole body X-ray irradiation of 100 to 400 rads. After weaning they were fed either basal diet or a diet containing 0.05% phenobarbital as a promoter. X-rays induced numerous adenosine triphosphatase-deficient islands appearing in the liver by wk 22 of age. However, they were generally small, gamma-glutamyl transpeptidase-negative, and did not clearly respond to the promoting stimulus of phenobarbital. No hepatic tumors were observed by 22 mo after radiation, even in phenobarbital-treated animals. Thus the X-ray-induced enzyme-altered islands differ somewhat qualitatively from those induced by potent hepatic carcinogens and their preneoplastic potential if at all present may be very low. Similarities between these X-ray-induced lesions and some types of spontaneous enzyme-altered islands are pointed out.
为了阐明X射线在这种动物中诱导肝细胞癌无效的原因，研究了X射线诱导大鼠肝脏癌前病变的潜力。8或22日龄的雄性新生大鼠接受100至400拉德的全身X射线照射。断奶后，它们被喂食基础饮食或含有0.05%苯巴比妥作为促癌剂的饮食。到22周龄时，X射线诱导肝脏中出现大量三磷酸腺苷酶缺乏岛。然而，它们通常很小，γ-谷氨酰转肽酶阴性，并且对苯巴比妥的促癌刺激没有明显反应。即使在苯巴比妥处理的动物中，辐射后22个月也未观察到肝肿瘤。因此，X射线诱导的酶改变岛在性质上与强效肝致癌物诱导的岛有所不同，并且它们的癌前潜力（如果存在的话）可能非常低。指出了这些X射线诱导的病变与某些类型的自发性酶改变岛之间的相似性。
