Short-term Toxicity Studies on 3-tert-butylphenyl-N-methyl-carbamate in the Rats and Mice

Abstract

3-tert-butylphenyl-N-methyl-carbamate (TBMC) was mixed in the animal diet CA-1 (Nippon CLEA Co.) in various concentrations (A: control, B: 4.5, C: 17, D: 50, E: 150, F: 450, G: 1350ppm) and cylindrical type diets were made. These were fed to rats and mice for 3 months and toxicity tests were carried out.
TBMC added to the diet did not affect daily food consumption. Average intake of TBMC in the highest groups reached half of the LD₅₀ values. Death rate of male rats and mice in the groups divided according to the concentration of TBMC did not reveal a significant difference. However in famale mice, a slightly higher death rate was observed in groups in which a greater amount of TBMC had been administered.
After 3 months of feeding observation was made determination of GOT, GPT, serum cholinesterase activity, haematocrit, haemoglobin content, erythrocyte and leucocyte counts were carried out, and no effects of TBMC could be observed. At autopsy, necrosis, abscess and bleeding in lung, probably due to pneumonia was observed. These findings were distributed at random in both experimental and control groups. Histological changes in organs other than the lungs could not be observed. No effect was observed with regard to weight of each organs.
Growth rate was not affected in male rats, but F and G groups in the female rats were inhibited (over 450ppm, 33.66mg TBMC/kg per day). In male mice, E, F and G groups (27.55mg TBMC), a lessered growth rate was observed.
Results of the above experiments reveal a minimum toxic level of 150ppm of TBMC was established in the diet for 3 months, a level equivalent of 27.6mg/kg per day. A zero effect level is 50ppm TBMC or 9.67mg/kg per day.