Sex differences in adrenocortical structure and function. XXV. Quantitative analysis of ACTH-immunoreactive cells in the anterior pituitary of gonadectomized and gonadal hormone replaced male and female rats.

Coupled immunocytochemical and stereologic studies of ACTH-immunoreactive cells were performed on anterior pituitaries of control male and female rats and on gonadectomized and testosterone or estradiol replaced animals. The average area and average volume of studied cells as well as their number were similar in anterior pituitary glands of control male and female rats. Orchiectomy increased average area of ACTH-immunoreactive cells, an effect reversed by testosterone while neither ovariectomy nor estradiol replacement had an effect on the area of studied cells. Average volume of these cells was similar in all experimental groups studied. Orchiectomy lowered the total number of ACTH-immunoreactive cells in the gland, an effect reversed by testosterone. Also ovariectomy lowered their number while after estradiol they were more numerous, even in comparison with control females. There is no significant correlation between the size and total number of ACTH-immunoreactive cells of the rat anterior pituitary gland and the size of the adrenal gland in both, male and female control, gonadectomized and testosterone or estradiol replaced rats.