Interrelations of dietary and hormonal effects in aging

A model system is proposed which suggests that aging involves a genetically programmed process encoded within specific regions of the central nervous system and is characterized by a gradual ascendency of inhibitory over excitatory influences. The resulting neural suppression reduces tonic stimulation to the hypothalamus-pituitary-endocrine axis, the autonomic nervous system and the spinal cord, and promotes the secretion of inactive pituitary hormone, the involution of the somatic musculature (smooth, cardiac and striated) and the compromise of secretomotor function. Experimental observation from nutritional restriction studies which include the prolongation of the life-span and delays in reproductive and homeostatic aging, degenerative coat changes and the appearance of neoplasia, are considered from the perspective of this hypothesis.