5-Ethylidene-2-norbornene was studied for oral toxicity in rats in a 28-day repeat dose toxicity test at doses of 0, 4, 20 and 100 mg/kg/day.
In the 100 mg/kg group, one male was sacrificed in a moribund condition, one male died, and body weight gain was suppressed in both sexes. Urinalysis revealed an increase in the number of animals with protein-positive urine in both sexes and a decrease in water consumption in males given 100 mg/kg. Blood chemical examination revealed a decrease in the a1-globulin level in males given 20 and 100 mg/kg and females given 100 mg/kg. At autopsy, pale discoloration of the kidneys was observed in males given 100 mg/kg, and relative kidney weights were increased in both sexes given 100 mg/kg. Histopathological examination revealed increased hyaline droplets in proximal tubular epithelium in the kidneys, and hypertrophy of follicular epithelium, as well as decrease in colloid or irregular shape of follicles in the thyroids in males given 4 mg/kg or more. Hypertrophy of follicular epithelium and decrease in colloid were also observed in females given 100 mg/kg.
The NOELs for repeat dose toxicity are considered to be below 4 mg/kg/day for males, and 20 mg/kg/day for females.
|Test method||:||Guideline for 28-Day Repeated Dose Toxicity Test in Mammalian Species (Chemical Substances Control Law of Japan)|
|Doses||:||0(Vehicle), 4, 20, 100 mg/kg|
| Number of animals/group|
|:||Males, 5; females, 5|
|Recovery period||:||Males and females; 7 and 7/group for the 0 and 100 mg/kg cases, respectively|
|Administration period||:||Males and females, 28 days|
|Terminal kill||:||Days 29 or 43|
|1)||The test was performed by the Safety Research Institute for Chemical Compounds Co., Ltd., 363-24, Shin-ei, Kiyota-ku, Sapporo, Hokkaido, 004-0839, Japan. Tel +81-11-885-5031 Fax +81-11-885-5313|