[Embryotoxicity and the immunodepressive action of tetracycline and its epi- and anhydro- derivatives].

The toxic effect of tetracycline and its epi- and anhydro-derivatives on growing chick embryos and the spleen cells of immunized mice was studied. High acute toxicity of 4-epianhydrotetracycline with respect to the chick embryos was found. Its LD50 was 4.8 times lower than toxicity of tetracycline hydrochloride. The characteristics of the acute toxicity was confirmed by the data on the embryo survival by the time of hatching. The same survival rate, i. e. 12 per cent was observed with the use of tetracycline and 4-epianhydrotetracycline in doses of 1000 and 100gamma per embryo respectively. Comparative investigation of the effect of tetracycline and anhydrotetracycline on the spleen cells revealed high toxicity of anhydrotetracycline which induced the same decrease in the number of the antibody-producing cells as tetracycline when used in doses 40 to 100 times lower than those of tetracycline. High toxicity of the anhydro-derivatives of tetracycline was also observed with respect to their teratogenic effect. Extremely pronounced anomalies in the embryo development were observed after exposure to 500gamma of 4-epianhydrotetracycline.