Alterations in oxygen consumption, respiratory quotient, and heat production in long-lived GHRKO and Ames dwarf mice, and short-lived bGH transgenic mice

J Gerontol A Biol Sci Med Sci. 2009 Apr;64(4):443-51. doi: 10.1093/gerona/gln075. Epub 2009 Mar 13.

Abstract

Growth hormone (GH) signaling influences longevity in mice, with decreased GH signaling associated with longer life span and increased GH signaling with shortened life span. A proposed mechanism through which GH signaling influences life span postulates that decreased GH signaling lowers metabolic rate, thus slowing aging by decreasing production of damaging free radicals. The influence of altered GH signaling on metabolism was tested by monitoring oxygen consumption (VO(2)), respiratory quotient (RQ), and heat production in long-lived GH receptor knockout (GHRKO) and Ames dwarf mice, and short-lived bovine GH-overexpressing transgenic (bGH TG) mice. Intriguingly, both GHRKO and Ames dwarf mice have increased VO(2) and heat per gram body weight, and decreased RQ, whereas bGH TG mice have decreased VO(2) and heat per gram body weight and increased RQ. In conclusion, decreased GH signaling associates with increased metabolism per body weight and may beneficially affect mitochondrial flexibility by increasing the capacity for fat oxidation; generally, GH excess produces opposite metabolic effects.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / genetics
  • Aging / physiology*
  • Animals
  • Calorimetry, Indirect
  • Dwarfism / genetics
  • Longevity / genetics*
  • Male
  • Mice
  • Mice, Knockout
  • Mice, Mutant Strains
  • Mice, Transgenic
  • Models, Animal
  • Oxygen Consumption / physiology*
  • Probability
  • Pulmonary Gas Exchange
  • Random Allocation
  • Receptors, Somatotropin / metabolism*
  • Sensitivity and Specificity
  • Signal Transduction / genetics
  • Thermogenesis
  • Thyroid Hormones / metabolism

Substances

  • Receptors, Somatotropin
  • Thyroid Hormones