TY - JOUR T1 - ACUTE TOXICITY OF THIOUREA TO RATS IN RELATION TO AGE, DIET, STRAIN AND SPECIES VARIATION JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 195 LP - 202 VL - 83 IS - 3 AU - SALLY H. DIEKE AU - CURT P. RICHTER Y1 - 1945/03/01 UR - http://jpet.aspetjournals.org/content/83/3/195.abstract N2 - 1. In acute thiourea poisoning the median lethal dose, when administered under identical conditions, varied greatly from one kind of rat to another. It was 4 milligrams per kilogram for tame Norway rats from our colony, 44 for tame Norway rats from Dr. E. B. Astwood's colony at Harvard, and more than 1200 for wild Norway and wild Alexandrine rats, when all were being fed our stock laboratory diet. 2. When Dr. Astwood's rats were raised and maintained on Purina Fox Chow they showed greater resistance to thiourea: the median lethal dose became 640 milligrams per kilogram compared to 44. Little difference was observed, however, between wild Norway rats which had been eating their normal forage outdoors, and those fed our stock diet three or four weeks. 3. Dr. Astwood's rats and our own exhibited pulmonary edema and pleural effusion as the main toxic symptoms. The wild Alexandrine rats showed little or none of either symptom. The amount of both of these effects was slightly increased in wild Norway rats by feeding them our stock diet. 4. Suckling rats and weanling rats up to 2 months of age from our own colony withstood doses of thiourea between 200 and 400 times as high as killed adults of the same strain under identical conditions. ER -