Thiosemicarbazide Toxicity in Mice. ∗

Abstract

Summary

1. Fatal convulsions follow the administration of doses of 20 mg of thiosemicarbazide (TSC)/kg or more to mice. 2. Semicarbazide is approximately 1/20 as toxic as thiosemicarbazide, while aminoguanidine produces no toxic symptoms at a dose of 650 mg/kg. 3. The toxicity of thiosemicarbazide is completely reversed by stoichiometric doses of pyridoxamine administered either orally, intraperitoneally or subcutaneously. The administration of pyridoxamine is effective either preceding or following the dosage with TSC at appropriate intervals. 4. Dietary B₆NH₂ deficiency does not influence the toxicity of TSC. 5. Pyruvic acid, α-ketoglutaric acid, γ-aminobutyric acid, glutamic acid, glucose and calcium chloride did not reverse the toxicity of TSC nor enhance the activity of suboptimal doses of pyridoxamine.