Aging of the human adrenal cortex

The aging of the human adrenal cortex presents several problems of interest to the cell biologist, as the interplay of changes in growth, differentiation, apoptosis and cellular senescence affect the properties of the tissue over the life span. The human adrenal cortex also presents an interesting case of tumor progression, as nodules and adenomas are very common in aging, although carcinomas are rare. A specific puzzle for the gerontologist is the loss of biosynthesis of dehydroepiandrosterone (DHEA) and its sulfate by the human adrenal cortex in aging. The reason for the development of a specific zone of DHEA-secreting cells, the zona reticularis, in childhood and the later involution of this zone is completely unknown. This review explores these issues, the underlying basic cell and molecular biology, and the techniques that can address these questions.