Effects of estradiol on adrenal cortex and medulla of the rat. Morphometric studies

Eight-week-old male and female Sprague Dawley rats are treated with 10 micrograms estradiol daily i.p. for 2 and 4 weeks respectively. Under treatment pituitary and adrenal weight increases in males and similates to those of females. As a relative measure for the cell sizes in the different zones of the adrenal cortex the number of nuclei/constant area is determined. In the outer zona fasciculata estradiol leads to a feminization of cell pattern in males with increase of cell sizes and partly also development of a female liposome pattern. An increase of cell sizes in the zona reticularis between the second and fourth week of treatment is restricted to male animals. In the zona glomerulosa cell sizes increase in males between the 10th and 12th week of life, independent of estradiol. In both sexes estradiol causes a significant dilatation of sinusoids of adrenal medulla. Most of the findings can be explained by known biochemical aspects of corticosterone metabolism of the rat.