Ultramorphometric studies of the adrenal cortex of adult rats after neonatal administration of sex steroids.

The outer zona fasciculata of 28 Sprague-Dawley rats, 8 weeks old, was studied by means of ultramorphometry. Four males and 4 females each received 1250 mug of testosterone proprionate (TP) or 300 mug oestradiol benzoate (OeB) on the second day of life. Four males and 4 females in oestrus or dioestrus served as controls. The controls showed both sex and cyclic differences: in comparison to the males, females displayed a finely dispersed lipoid pattern; enlargement of the nucleus and an increase in the amount of smooth endoplasmic reticulum (SER) indicated an increased stimulation of the cortex during oestrus. Neonatal administration of TP in females causes a distinct enlargement of cells with an increase in the volumes of nucleus, mitochondria, liposomes, SER and liposomes. The mitochondria and liposomes show a small-dispersed pattern of distribution. All these function-specific morphometric parameters point to an increased activity of the individual cell. The changes are less pronounced after OeB than after TP. In the male, neonatal administration of sex steroids results in an alteration of the sizes of the mitochondria and liposomes. The liposomes are distributed finely dispersed. At the same time there is an increase in the lipoid content. According to these parameters, fasciculata cells fulfil the morphological conditions that are a prerequisite for an elevated functional reaction. This change is more marked following OeB than TP. Sex dimorphism is preserved following neonatal application of sex steroids since the alterations are much more pronounced in females than in males.