REMOTE CONSEQUENCES OF ADMINISTRATION OF NITROSOMETHYLUREA TO NORMAL MICE AT EXTRA LOW-DOSES

Time-related changes in essential internal organs (spleen, thymus, liv er, kidney, and lung) and peripheral blood cells (leucocytes and lagre granular lymphocytes) were studied in healthy mice for 50 days after a single injection of 10(-15) M water solution of nitrosomethylurea. M ass and cellularity fluctuations were induced. The longest fluctuation period was 45 days (for the lung) and the shortest one was 15-20 days (for the liver and blood cells). Possible consequences of treatment w ith extra low doses of the biologically active drug for the organism a re discussed.