Different doses of estron (El) were administered to 97 F344 and wistar rats. After 30, 45 and 60 days, the weight and histological change in the pituitary gland were observed.

• 本实验给97只不同性别的F344和Wistar大白鼠投以不同剂量的雌酮,用药后30、45和60天时,分别观察脑垂体重量及组织学变化。