SEX DIFFERENCES OF THE RESPONSE OF THE ADRENAL GLAND OF THE RAT TO MESENCEPHALIC LESIONS

Abstract

ABSTRACT The pituitary-adrenal system of adult rats of both sexes bearing small bilateral electrolytic lesions in the periaqueductal gray matter of the mesencephalon (PGM) was studied. Female animals showed a significant increase in the weight of the adrenal gland and in the number of mitoses; there was a marked diminution of histochemically detectable alkaline phosphatases and variations in simple esterases, neutral fats and cholesterol. Conversely, male animals with similar nervous lesions did not show adrenal hypertrophy or changes in its mitotic count and only slight variations in the lipid content. The administration of small doses of oestradiol dipropionate (2 μg/rat/d) to male induced slight changes in only some of the parameters studied. When oestrogen was given to animals bearing lesions in the PGM, a significantly larger adrenal hypertrophy was obtained than in the preceding case, but with an increase of capillary alkaline phosphatases. These results suggest that the central neural control of corticotrophin secretion in the rat is different in both sexes and that oestrogen could be one of the factors involved in such a difference.