THE EFFECTS OF ESTRADIOL AND HUMAN CHORIONIC GONADOTROPIN ON ACTH CELLS IN PERIPUBERTAL FEMALE RATS: A HISTOLOGICAL AND STEREOLOGICAL STUDY

Abstract- The effects of estradiol (EDP) and human chorionic gonadotropin (HCG) on histological and stereological fea-tures of adrenocorticotropic (ACTH) cells in peripubertal female rats were examined. The first group of females received five injections of EDP (0.25 mg/kg b.w.), every second day from the 4th to 14th day after birth, and was killed at the peripu-bertal stage. The second group of females was given two injections of pregnyl-gonadotrophinum chorionicum (HCG; 50 IU/kg body weight) on the 36th and 37th days after birth, and it was killed 24 h after the last treatment. The controls were injected with an equivalent volume of the corresponding vehicle. ACTH cells were immunohistochemically labeled and stereologically evaluated. Stereological analysis showed that the volume of ACTH cells and their volume density in peripu-bertal females treated with EDP, were decreased by 15.6 % and 53.8 % (p<0.05), respectively, compared to the controls. In HCG-treated animals, the observed parameters were increased by 39.2 % and 15.4 % (p<0.05), respectively, in comparison with the control females. These findings suggest that the application of EDP or HCG exerted opposite effects on the stereo-logical features of pituitary ACTH cells