Metabolism of [14C]permethrin in rats studied by liquid scintillation counting

[I4C]permethrin was given intragastrically to rats. The radioactivities of tissue samples were determined by liquid scintillation counter. The dynamic distribution of radioactivity in the body showed that the drug was absorbed rapidly. At first it was chiefly distributed in liver and kidneys. After 24 h its concentration in adipose tissue was elevated. About 95% of the administered radioactivity was excreted in 4 d. Only traces remained in the adipose tissue. After [14C]permethrin was given ig to rats daily for 7 consecutive days, it was mainly accumulated in adipose tissue. The radioactivity was rapidly excreted. The total elimination in the first 6 d after the discontinuance of medication was almost complete, and only trace remained in the adipose tissue.