You are here:
AGE-DEPENDENT DIFFERENCES IN THE SUSCEPTIBILITY OF RATS TO DELTAMETHRIN
Citation:
Sheets, L., J. Doherty, M. Law, L.W. Reiter, AND K. Crofton. AGE-DEPENDENT DIFFERENCES IN THE SUSCEPTIBILITY OF RATS TO DELTAMETHRIN. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/053.
Description:
Separate groups of weanling and adult rats were exposed to both behaviorally-active and lethal doses of deltamethrin to examine age-dependent toxicity of a pyrethroid over a wide dose range. he acoustic startle response (ASR) was selected for comparison at low doses since it is a sensitive, quantifiable biological indicator of pyrethroid effects in rats. cute mortality was included for comparison at the upper limit of the dose-response. eltamethrin was administered by gavage as a single dose in corn oil for all tests. ffects on the ASR were comparable in 21- and 72-day-old rats, with a 4 mg/kg dose decreasing ASR amplitude by approximately 50% (ED50) at both ages. y comparison, LD50 values in 11-, 21- and 72-day-old male rats were 5.1, 11, and 81 mg/kg, respectively. Thus, 11- and 21-day-old male rats were 16- and 7-times, respectively, more sensitive than adults to acute lethality. he concentration of deltamethrin was measured in whole-brain tissue from weanling and adult males treated with ED50 and LD50 doses. he brain concentration of deltamethrin at the ED50 dose of 5 mg/kg was higher in weanling rats than adults. his suggests a possible functional difference, with weanling rats