[Age and ultrastructural features of adrenal capillaries in rats following ACTH administration and in insulin shock].

Electron microscopy was used to study age-associated features of blood capillaries of adrenal cortical substances and adrenal medulla in adult and old rats during ACTH administration and insulin shock. It has been revealed that as a result of an increase in adrenal function of the adult rats, endotheliocytes of cortical substance and medulla developed ultrastructural changes promoting the intensification of transcapillary metabolism. The old rats showed pathological changes in the endotheliocyte ultrastructure, responsible for the development of capillary insufficiency of the adrenals during stimulation of their secretory activity.