The human hypothalamo-neurohypophyseal system in relation to development, aging and Alzheimer's disease.

The research reviewed in the present paper indicates that vasopressin and oxytocin cells in the human HNS constitute an extremely stable population of neurons throughout the human life span. Increases in the activity of these cells, which are probably related to maturation of the system were observed during fetal development and probably extend well beyond term. During senescence an increase in the activity of the vasopressin cells in the human HNS was observed which is probably a compensation for age-related changes in kidney function. These data do not support a role of declining vasopressin secretion in age-related memory decline. Although there is some evidence for an impairment of vasopressin synthesis and release in Alzheimer patients, vasopressin cell numbers in Alzheimer's disease do not fall below values observed in young controls. Furthermore, peripheral administration of vasopressin or vasopressin analogues to AD patients have not yielded consistent results.