Objective To investigate the changes of estrogen receptors (ER) in thymus of 7-week old female BalB/c mice after having been treated with diethylstilbestrol (DES) in their neonatal period. Methods Neonatal female BALB/c mice were injected DES hypo 5 days after birth. They were killed on the 49th days to study the changes in ER by immunohistological technique. Results It was found that the administered DES increased the level of estrogen receptor in thymus. Conclusion Estrogen acts on thymus mainly throu...