The ultrastructural features of secretory cells of some endocrine glands in aging.

In the electron microscopic investigation of the secretory cells of adenohypophysis, adrenal cortex, adrenal medulla and pancreatic islets from the adult and old Wistar male rats, certain age-related ultrastructural features have been found. Age changes appeared to be more pronounced in the thyrotrophs, somatotrophs and gonadotrophs of the adenohypophysis and in zona glomerulosa and zona reticularis spongiocytes of the adrenal cortex. They consisted of atrophy of the Golgi apparatus, appearance of the cytoplasmic vacuoles, lipid and lipofuscin granules, secondary lysosomes and damage of the inner mitochondrial membrane. Parallel to these, hypertrophy of the Golgi apparatus and rough endoplasmic reticulum, formation of giant mitochondria and presence of a great number of secretory cells in the cellular cytoplasm were noted in zona fasciculata spongiocytes and chromaffin cells of the adrenal medulla, and in beta cells of the pancreatic islets during aging thus evidencing for the adaptive changes in the ultrastructure of these cells. However, no appreciable age changes have been observed in the ultrastructure of the adrenocorticotropic cells of the adenohypophysis.