Abstract
In the present work, the authors injected 1-methyl-2-mercaptoimidazole subcutaneously into mice, and observed the animals for 72 hours to investigate the toxicity. The authors further investigated the histological changes in the thyroid gland and liver. The following conclusions were thus drawn.
1) When more than 8.0 mg of the drug was injected, the animals became fatal within 48 hours from the injection. The LD50 at 72 hours was 4.45±0.02 mg per 10 g of body weight.
2) As the only finding in the thyroid gland in the case with the injection of low concentration of the drug, milder solidness of the follicles was observed as compared with that in the case with the injections of higher concentration of the drug. Excepting the above, no particular findings were recognized. However, as the concentration became higher, more follicles became poligonal in shape with more solidness, showing a tendency of vanishing vacuoles. Further, the follicular epithelium became higher, and the proliferation of the newly formed cells and a slight desquamation of epithelial cells were observed. The diminution in the function of thyroid gland was also recognized. Furthermore, at the concentration of approximately the LD50, the colloid was found deeply stained by eosin when stained with hematoxylin-eosin stain.
3) As the finding in the liver in the case with the injection of lower concentration, fatty degeneration of the liver cells, and perivascular and interstitial round cells infiltration were observed. As the concentration became higher, the congestion of the blood vessels became more eminent, various degenerative changes of the liver cells such as granular degeneration, fatty degeneration, necrosis or necrosis-like changes were recognized.
