title: The somatotropic axis and aging: Benefits of endocrine defects.
abstract: Reduced somatotropic [growth hormone (GH) and insulin-like growth factor-1 (IGF-1)] action has been associated with delayed and slower aging, reduced risk of frailty, reduced age-related disease and functional decline, and with remarkably extended longevity. Recent studies have added to the evidence that these relationships discovered in laboratory populations of mice apply to other mammalian species. However, the relationship of the somatotropic signaling to human aging is less striking, complex and controversial. In mice, targeted deletion of GH receptors (GHR) in the liver, muscle or adipose tissue affected multiple metabolic parameters but failed to reproduce the effects of global GHR deletion on longevity. Continued search for mechanisms of extended longevity in animals with GH deficiency or resistance focused attention on different pathways of mechanistic target of rapamycin (mTOR), energy metabolism, regulation of local IGF-1 levels and resistance to high-fat diet (HFD).
authors.affiliation: SIU School of Medicine, Department of Internal Medicine, 801 N. Rutledge, P.O. Box 19628, Springfield, IL 62794-9628, United States. Electronic address: abartke@siumed.edu.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bartke
authors.affiliation: Edison Biotechnology Institute, Ohio University, Athens, OH 45701, United States; Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, United States.
authors.forename: Edward O
authors.initials: EO
authors.lastname: List
authors.affiliation: Edison Biotechnology Institute, Ohio University, Athens, OH 45701, United States; Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, United States.
authors.forename: John J
authors.initials: JJ
authors.lastname: Kopchick
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D004703:Endocrine System / Q000502:physiology*; D004734:Energy Metabolism; D013006:Growth Hormone; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008136:Longevity / Q000502:physiology*; D051379:Mice; D011986:Receptors, Somatotropin / Q000378:metabolism*
chemical_list: D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone
keywords: Adipose tissue; Growth hormone; Growth hormone receptors; IGF-1; Liver; Longevity; Muscle