[Investigations on the mutagenic effect of triethylenemelamine (TEM) on early embryonic tissue and bone marrow of the rat by chromosome analysis (author's transl)].

Female rats were treated with triethylenemelamine (Tretamine; TEM) with a dose of 0.4 mg/kg body weight and 0.6 mg/kg body weight respectively on days 1, 2, 3; 3, 4, 5 or 6, 7, 8 post coitum. The animals were slaughtered on day 9 or pregnancy. Corpora lutea and living and dead embryos were counted to estimate embryonic loss. Thereafter chromosome-analysis of bone marrow cells and embryonic tissue took place. Highter TEM dosage increased the rate of embryonic loss. It increased from 28.1% with a dose of 3 X 0.4 mg TEM to 75.7% with 3 X 0.6 mg TEM. The level of embryonic loss depends on the time of treatment during different stages of early gestation. It was highest on the first 3 days and lowest on days 6-8 of gestation (0.4 mg TEM on -ays 1, 2, 3 p.c., 71.8%; 0.4 mg TEM on days 6, 7, 8 p.c., 2.9%). By the chromosome analysis, early embryonic tissue seemed to be more sensitive to TEM than bone marrow cells. The highest rates of numerical (35.7%) and (3 X 0.4 mg TEM). A higher dose induced a negative dose-effect, the frequency of aberrations decreased (3 X 0.6 mg TEM, 29% NUMERICAL AND 1.2% STRUCTURal aberrations). With increased embryonic loss (from 28.1% to 75%) structural aberrations decreased (from 5.7% to 1.2%). The time of treatment p.c. was highly correlated with the frequency of aberrations. It was highest with TEM application on days 6, 7, 8 of pregnancy; at the same time the mortality rate was lowest. The same tendencies were noted in the investigation of the chromosomes from bone marrow cells.