title: Ageing as upregulation failure.
abstract: This paper investigates similarities in physiological senescent changes in various mammalian organ systems and relates these to postulated mechanisms of age modulation. It proposes that the observed decline in homeostasis with age is due to an inability of target cells, of neural, endocrine and other forms of control, to upregulate after their downregulation. The well-documented flattening of circadian rhythms with age, particularly the loss of the sustained diurnal hypothermic phase, is described as integral to such change, and maintenance or induction of certain youthful circadian patterns is proposed as a means of restoring homeostasis in senescence and other conditions.
authors.affiliation: Department of Veterinary Pathology, University of Sydney, NSW, Australia.
authors.forename: M F
authors.initials: MF
authors.lastname: MacGibbon
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D002940:Circadian Rhythm; D004702:Endocrine Glands / Q000254:growth & development / Q000502:physiology; D006706:Homeostasis; D006801:Humans; D008322:Mammals; D008954:Models, Biological; D009420:Nervous System / Q000254:growth & development; D009424:Nervous System Physiological Phenomena