The teratogenic activity of the herbicide 3-amino-1,2,4-triazole (Amitrole) was tested by injecting aqueous solutions into the yolk sac of chicken eggs at 0, 24, 48, and 96 hours of incubation. The toxicity of Amitrole was relatively high at 0 hours, moderate at 24 and 48 hours, and very high at 96 hours. It showed clear dosage dependence. The principal malformations produced by Amitrole concern the beak. Abnormalities of the tibia shaft occurred as a much less common defect. With a dosage of 20 mg/egg at 0, 24, and 48 hours of incubation Amitrole led to a relatively low incidence of malformations, but this was followed by a threshold to high teratogenicity at 96 hours. Treatment with 40 mg/egg of the teratogen, on the other hand, produced at all stages between 0 and 96 hours a similarly high incidence of beak defects. A series of compounds tested as supplement to Amitrole was of no avail in reducing teratogenicity. A comparison of dimethyl sulfoxide and water as solvents of Amitrole showed that in the former the compound is much less detrimental to chick development than in the latter. © 1972.
Landauer, W., Salam, N., & Sopher, D. (1971). The herbicide 3-amino-1,2,4-triazole (Amitrole) as teratogen. Environmental Research, 4(6), 539–543. https://doi.org/10.1016/0013-9351(71)90014-4