Growth hormone signaling is necessary for lifespan extension by dietary methionine
Abstract
Growth hormone significantly impacts lifespan in mammals. Mouse longevity is extended when growth hormone (GH) signaling is interrupted but markedly shortened with high-plasma hormone levels. Methionine metabolism is enhanced in growth hormone deficiency, for example, in the Ames dwarf, but suppressed in GH transgenic mice. Methionine intake affects also lifespan, and thus, GH mutant mice and respective wild-type littermates were fed 0.16%, 0.43%, or 1.3% methionine to evaluate the interaction between hormone status and methionine. All wild-type and GH transgenic mice lived longer when fed 0.16% methionine but not when fed higher levels. In contrast, animals without growth hormone signaling due to hormone deficiency or resistance did not respond to altered levels of methionine in terms of lifespan, body weight, or food consumption. Taken together, our results suggest that the presence of growth hormone is necessary to sense dietary methionine changes, thus strongly linking growth and lifespan to amino acid availability.
From the paper
- Result
GHRKO mice lived 1055 days (95% CI 1010–1170 days) and wild-type mice lived 854 days (95% CI 772–906 days), representing a 24% difference.
Results, Lifespans of Ames dwarf, GHRKO, and GH transgenic mice
- Harms
Beginning at 8 weeks of age, three levels of methionine were provided to mice to represent a severe restriction (0.16%), approximately 50% reduction (0.43%) compared with standard rodent diets and more achievable in human diets, and an enriched level (1.3%) that remained below toxicity levels.
Quoted word for word from the full text on PubMed Central.
The paper
University of North Dakota
Aging Cell, 19 Sep 2014, Open access
