High incidence of angiosarcomas in brown-fat tissue and livers of mice fed sterigmatocystin.

BDF1 female mice fed 30 or 120 ppm sterigmatocystin in their diet for 55 or 51 wk, respectively, developed angiosarcomas of the liver and of the dorsal brown-fat tissue. No tumours were observed in five mice from each group, including the controls, killed after 43 wk, but angiosarcomas were observed in mice from the test groups that died or were killed after more than 43 wk of treatment with sterigmatocystin. Thirty-four out of 53 mice (64.2%) fed 30 ppm sterigmatocystin developed hepatic angiosarcomas. Six (11.3%) of those fed 30 ppm sterigmatocystin and 27 out of the 51 mice (52.9%) fed 120 ppm developed angiosarcomas in the dorsal brown-fat tissue. Benign vascular lesions in the liver and a few angiosarcomas of the ovary and lung were also observed in mice of both test groups. No vascular changes were observed in control mice except for peliosis-like lesions in the spleens of two mice. Increases in the incidences of lung and hepatocellular adenomas were also observed in sterigmatocystin-treated mice.

Toxicity of propoxur to rats by subacute inhalation.

Male and female rats were exposed to propoxur (2-isopropoxyphenyl-N-methyl-carbamate) aerosol, concentrations averaging 5.7, 18.7 and 31.7 mg/m3 air, for 6 hours daily on five days in a week over a period of 12 weeks. The effects were depressions of plasma by 20 to 30%, and of erythrocyte and brain cholinesterase activities which were caused by the highest air concentration of 31.7 mg/m3. On the basis of the physical, biochemical, phamacokinetic and metabolic behaviors of propoxur, a maximum allowable concentration of 2.5 mg/m3 air is suggested.