[Thymus changes in chicks following treatment with small doses of insecticides].

Effects of small doses of insecticides (Fenclorfos and Heptaclor) upon the thymus of chickens were followed. Treatment began at the age of 3 weeks and continued during 4 or 8 weeks. Doses used were: 1 ppm for Heptaclor and 1 ppm and 0.5 ppm for Fenclorfos. Total nucleic acid, total protein, RNA, DNA, and amino acid nitrogen contents were determined, as well as GOT and GPT activities and weight of the organ. Results are interpreted as being due to the action of insecticides on the hypothalamus-hypophysis-adrenals axis. They depend on the nature and dosis of insecticide, as well as on the duration of the treatment.