Arnold D L, Krewski D R, Junkins D B, McGuire P F, Moodie C A, Munro I C
Toxicol Appl Pharmacol. 1983 Feb;67(2):264-73. doi: 10.1016/0041-008x(83)90233-8.
Groups of 50 male and 50 female Sprague-Dawley rats were fed diets containing 0, 75, 100, or 150 ppm ethylenethiourea (ETU) for 7 weeks, at which time subgroups of 10 animals from each group were killed. Subsequent subgroups of 10, 10, and 20 animals were killed after an additional 2, 3, and 4 weeks, respectively, on the control diet in order to examine whether the toxicological effects induced by ETU were reversible. In both sexes, the mean body weight and feed consumption were significantly decreased in all treated groups, while the mean thyroid weight (absolute as well as relative to both body and brain weight) appeared to increase linearly with dose. Mean T4 blood levels in animals fed 150 ppm ETU were significantly below those in controls. The magnitude of the changes in body weight, thyroid weight, and T4 blood levels observed during the first 7 weeks of the study decreased after ETU was removed from the diet. The statistical procedures developed and applied here may be useful in other experiments designed to assess the reversibility of other toxicological endpoints.
将50只雄性和50只雌性斯普拉格-道利大鼠分为几组，分别喂食含有0、75、100或150 ppm乙撑硫脲（ETU）的饲料7周，此时每组选取10只动物的亚组处死。随后，另外10只、10只和20只动物的亚组分别在额外的2周、3周和4周后在对照饲料喂养下处死，以检查ETU诱导的毒理学效应是否可逆。在两性中，所有处理组的平均体重和饲料消耗量均显著降低，而平均甲状腺重量（相对于体重和脑重的绝对值以及相对值）似乎随剂量呈线性增加。喂食150 ppm ETU的动物的平均血清T4水平显著低于对照组。在研究的前7周观察到的体重、甲状腺重量和血清T4水平变化的幅度在从饲料中去除ETU后降低。此处开发和应用的统计程序可能对其他旨在评估其他毒理学终点可逆性的实验有用。
