Age-dependent retention of [14C]DDT in the brain of the postnatal mouse

Postnatal mice, at the age of 0 (newborn), 3, 7, 10, 15, 20 and 55 days, were given a single administration of dichlorodi[U-¹⁴C]phenyltrichloroethane ([¹⁴C]DDT; 1.48 MBq/kg body wt.) per os. They were killed 24 h or 1 week post-treatment and the amount of radioactivity in the brain was measured. The most pronounced retention was found in mice receiving [¹⁴C]DDT on the tenth postnatal day. The activity found after 1 week was as high as that observed after 24 h, and it was also highest in this age category even though older mice displayed a higher activity 1 day after administration.