Role of programmed cell death in the aging process: an unexplored possibility.

The possibility of cell death being a programmed event under neuroendocrine control during aging is discussed. Physiological cell death is currently regarded as a built-in cellular mechanism which can be triggered by extracellular signals. The term 'programmed cell death' is employed when these signals are involved in developmental or adaptive processes. Programmed cell death has a wide incidence throughout the animal kingdom, both during development and reproduction. Consequently, the involvement of such a basic cellular process in aging appears as a plausible possibility. The neuroendocrine system best qualifies as the potential regulator of cell death during aging. First, it is the major regulator of homeostasis and developmental processes in higher organisms. Second, in many instances physiological cell death has been shown to be under control of the neuroendocrine system during development and reproduction. Finally, this system is implied in the decline of several physiological functions during aging. The above considerations point to this unexplored topic as a promising avenue of gerontological research.