[Effect of stress (immobilization) on embryotoxic and teratogenic effect of 2,4,5-trichlorophenoxyacetic acid and its derivatives].

White female rats were injected intragastrically with 2,4,5-trichlorphenoxyacetic acid (2,4,5-T) in the dose of 400 mg/kg, commercial sample of butyl ester in the dose of 50, 100, 200 mg/kg and purified ester of 2,4,5-T in the dose of 800 mg/kg every day on the 9, 10, 11, 12, 13 and 14th day of gestation. Stress reaction (immobilization) was produced by fixation of the animals on a board modified by S. I. Renaud (1959) for 2 h after the injection of corresponding substances. The rats were killed on the 20th day and the number of alive and dead fetuses was registered. Under the conditions of immobilization embryotoxic effect of 2,4,5-T increased for certain on the 9th and 10th days (52.7% and 33.64%, respectively), that of butyl ester of 2,4,5-T--on the 10th day (55.66%). Immobilization increased teratogenic effect of 2,4,5-T on the 9th, 10th, and 11th days, that of butyl ester of 2,4,5-T on the 13th, 14th days. Purified butyl ester of 2,4,5-T proved to be 4 times less toxic and produced a severe embryotoxic and a mild teratogenic effect.