COMPARED EVENTS AND EFFECTS OF PERINATAL MATURATION AND OF AGING ON THE HYPOTHALAMO-PITUITARY-ADRENAL AXIS

In response to environmental changes and to different stress, corticos teroid secretion is stimulated for recovering homeostasis. This secret ion needs a good functioning of all implicated structures : hypothalam us secreting CRH and ADH, pituitary secreting ACTH, central nervous sy stem and its aminergic tract, the negative feedback of corticosteroids acting at different levels : hippocampa, hypothalamus and pituitary. Maturation of these structures and their interrelations is carried out during the perinatal period with anatomical and biochemical changes i mproving hormonal effectiveness at their target. With aging, organism grow old more or less rapidly and the growing old of the hypothalamo-p ituitary-adrenal axis appeared only late in the life when this axis is hardly stimulated. This is expressed by a decrease of the uptake of h ormones by the cell membranes and in the APMc production, inducing a l ower adrenal response.