ISSN:
1573-7306
Keywords:
aging
;
hypothalamus
;
neurohypophysis
;
kidney
;
arginine vasopressin
;
morphology
;
physiology
;
review
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract This review examines the age-changes in the hypothalamo-neurohypophysial-renal system (HNRS) and their role in age-associated alterations in the regulation of water homeostasis. A comparative approach has been adopted. The structural characteristics of the magnocellular nuclei are well preserved and there is no evidence for a significant loss of neurons from this region. Studies of the release of anti-diuretic hormone from the neurohypophysis are contradictory. In rodents there is a decline in neuroaxonal transport of hormone from the hypothalamus to the neurohypophysis. It is concluded that for most purposes the ability to respond to acute changes in plasma osmolality are preserved in rodents and humans. There is little evidence to suggest an alteration in the pharmacokinetics of anti-diuretic hormone with advancing age. The renal medullary collecting ducts of rodents, and possibly humans, show a reduced sensitivity to hormonal stimulation. However the complexities of kidney regulation, regarding changes in blood flow, medullary osmotic gradients, and so forth, have barely been investigated. The review indicates the complexity of the age-associated changes that can be found between, and within, species in the HNRS. Whatever the explanation for the differences between species clearly there is a decline in function with time. This results in micro-environmental changes within the older organism that in turn will influence the efficiency and accuracy of other metabolic processes controlling homeostasis and the functions of other systems.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01509278
Permalink
