Alterations in oxygen consumption, respiratory quotient, and heat production in long-lived GHRKO and Ames dwarf mice, and short-lived bGH transgenic mice.
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.
Westbrook
Reyhan
R
Department of Internal Medicine, Division of Geriatric Research, Southern Illinois University School of Medicine, 801 North Rutledge Street, Springfield, IL 62794-9628, USA. rwestbrook@siumed.edu
Bonkowski
Michael S
MS
Strader
April D
AD
Bartke
Andrzej
A
D000375:Aging / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002153:Calorimetry, Indirect; D004392:Dwarfism / Q000235:genetics; D008136:Longevity / Q000235:genetics*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D023421:Models, Animal; D010101:Oxygen Consumption / Q000502:physiology*; D011336:Probability; D011659:Pulmonary Gas Exchange; D011897:Random Allocation; D011986:Receptors, Somatotropin / Q000378:metabolism*; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000235:genetics; D022722:Thermogenesis; D013963:Thyroid Hormones / Q000378:metabolism
D011986:Receptors, Somatotropin; D013963:Thyroid Hormones