[Experimental studies on the toxicity of tetrahydrofuran administered to animals by repeated inhalation]

The toxicity of tetrahydrofuran (THF) was evaluated by repeated inhalation experiments on rats. The animals were separated into a control group and groups exposed to 100, 200, 1,000 or 5,000 ppm THF for 4 hours a day, 5 days a week over a 12-week period. No significant differences appeared between the groups exposed to 100 ppm as well as 200 ppm and the control group, except for slight local irritant symptoms of the mucosa. The group exposed to 1,000 ppm showed an effect on the liver function according to the results by serum chemistry test. In the group exposed to 5,000 ppm, marked local irritant symptoms and morphological damage of the respiratory mucous membrane were found upon histological examinations. Also significant differences were noted between this group and the control group in white blood cell counts, blood sugar values and liver functions by hematological and serum chemistry tests.