1987 Volume 12 Issue 4 Pages 397-428
d·d-T80-prallethrin, a pyrethroid insecticide for sanitary use, was administered to Crj : CD (Sprague Dawley) rats at concentrations of 120, 600 or 3, 000 ppm in diet for one year to assess the chronic toxicity potential and the reversibility. The summarized results obtained are as follows : 1. Chronic toxicity study 3, 000 ppm : Decreases in body weight gain, food consumption, and water intake were observed. Slight alopecia in the neck and/or back was noticed during the first and second weeks, but the animals were recovered thereafter. Slight anemic changes such as decreases in hemoglobin concentration, hematocrit value, MCV and MCH were observed in the females3 at 52 week. Blood biochemistry revealed increases in total cholesterol (in the males and females at 13, 26 and 52 weeks), phospholipid (in the males and females at 13, 26 and 52 weeks), albumin (in the males at 13 and 26 weeks, in the females at 52 week), total protein (in the males at 26 week, in the females at 52 week), A/G ratio (in the males at 13 week, in the females at 26 week), creatinine (in the males at 52 week), urea nitrogen (in the females at 52 week), GOT (in the males and females at 52 week) and GPT (in the males and females at 52 week), and decreases in triglyceride (in the females at 26 and 52 weeks) and alkaline phosphatase (in the males at 13 and 52 weeks). In urinalysis, an increase in bilirubin was observed in the males at 52 week. Gross-pathology revealed a lower incidence of accentuated lobular pattern of liver (in the males at 26 week) and a higher incidence of enlarged liver (in the males at 52 week). In organ weight, increases in liver (in the males and females at 26 and 52 weeks), kidney (in the males at 26 and 52 weeks) and thyroid weights (in the males at 26 and 52 weeks, in the females at 26 week), and decreases in spleen (in the females at 26 and 52 weeks) and adrenal weights (in the females at 52 week) were observed. Histopathological examination revealed a lower incidence of fatty metamorphosis in the liver of females at 52 week. 600 ppm : An increase in liver weight was observed in the males at 26 week. 120 ppm : No effect was observed. 2. Reversibility study Almost all the above chronic toxicities were reversible. However, blood biochemistry revealed increases in albumin (in the females), A/G ratio (in the females) and creatinine (in the males) and a decrease in alkaline phosphatase (in the males) at 3, 000 ppm. Based on the above results, one year d·d-T80-prallethrin administration revealed slight toxic effects mainly in the liver, kidney and thyroid at the dose level of showing body weight gain suppresion. However, most of the toxic effects were reversible after 13-week withdrawal period. It is concluded that no-observed effect level is 600 ppm (43.3 mg/kg/day) for female and 120 ppm (7.16 mg/kg/day) for male.
