Doniach I
Br J Cancer. 1974 Dec;30(6):487-95. doi: 10.1038/bjc.1974.227.
Male rats were given 0, 100, 250 or 500 rad x-rays to the thyroid gland at 9-12 weeks of age and killed 18-20 months later. No thyroid tumours were found in the unirradiated animals, a few follicular adenomata developed after 100 and 250 rad and a follicular carcinoma after 500 rad. A similar group was set up and maintained on a diet with thyroxine added in a quantity to give a daily consumption of 5-6 μg/100 g body weight in order to suppress TSH secretion. Thyroid tumour production was considerably lowered. At the termination of the experiment the efficiency of the TSH suppression was tested by measurement in some rats of T/S (131)I concentration ratios and in others of the 24 h% (131)I thyroid uptake. In some rats TSH was totally suppressed, in others partially suppressed. A further group was set up and maintained on the goitrogen 0·1% aminotriazole in the drinking water to cause excessive TSH secretion. All its subgroups, including unirradiated animals, developed numerous follicular adenomata and carcinomata. Enhancement of carcinoma production was present in the 500 rad subgroup. It was concluded that the development of thyroid adenomata after the above doses of x-radiation may occur without an excessive rise in TSH secretion, that suppression of TSH lowers radiation tumour production and that therefore TSH may play a permissive role in the development of thyroid tumours following low dose x-radiation to the thyroid gland.
9至12周龄的雄性大鼠接受0、100、250或500拉德的甲状腺X射线照射，18至20个月后处死。未照射的动物未发现甲状腺肿瘤，100和250拉德照射后出现少数滤泡性腺瘤，500拉德照射后出现滤泡癌。设立了一个类似的组，给其喂食添加甲状腺素的饮食，使每日摄入量为5至6微克/100克体重，以抑制促甲状腺激素（TSH）分泌。甲状腺肿瘤的发生率显著降低。实验结束时，通过测量部分大鼠的T/S（131）I浓度比以及其他大鼠的24小时（131）I甲状腺摄取率来检测TSH抑制的效果。在一些大鼠中TSH被完全抑制，在另一些大鼠中则被部分抑制。又设立了一组，给其饮用含0.1%氨三唑的致甲状腺肿物质的饮水，以导致TSH分泌过多。其所有亚组，包括未照射的动物，都出现了大量滤泡性腺瘤和癌。500拉德亚组中癌的发生率有所增加。得出的结论是，上述剂量的X射线照射后甲状腺腺瘤的发生可能在TSH分泌没有过度升高的情况下出现，TSH的抑制降低了辐射性肿瘤的发生率，因此TSH可能在甲状腺低剂量X射线照射后甲状腺肿瘤的发生中起允许作用。
