Ames dwarf mice eat more food relative to their body weight than normal mice, even when food is freely available, and their longer lifespan is not caused by eating less but may result from...
Mechanism
Synthesis from 1 study
These mice are born with a genetic change that makes their bodies grow slower and use less energy. Because they don't burn energy fast, they don't get damaged as quickly, so they live longer—even though they eat more food than normal mice. Their bodies use the extra food to repair themselves...
Most probable mechanism
A genetic mutation causes the pituitary gland to produce less growth hormone, which lowers the levels of a growth-related protein in the liver. This slows down the body's energy use and body temperature, reduces the rate at which cells divide and accumulate damage, and makes the body more efficient at using food for maintenance instead of growth. As a result, the animal eats more food per pound of body weight but ages slower and lives longer.
A mutation in the Pit-1 gene impairs development of the pituitary gland, reducing secretion of growth hormone, prolactin, and thyroid-stimulating hormone
Reduced growth hormone decreases insulin-like growth factor 1 production in the liver
Lower insulin-like growth factor 1 and insulin signaling reduce cellular proliferation and anabolic activity
Metabolic rate and core body temperature decrease, reducing the production of oxidative damage to proteins, lipids, and DNA
Slower accumulation of molecular damage delays the onset of age-related diseases such as tumors
Energy from increased food intake is redirected from growth to maintenance and repair processes
Less supported by current evidence, but not ruled out
Reducing food intake increases physical activity and lowers body temperature, which improves cellular stress resistance and preserves brain function, extending lifespan beyond what is achieved by growth hormone deficiency alone.
Reduced food intake lowers circulating glucose and insulin levels
Lower insulin signaling activates pathways that enhance cellular repair and reduce inflammation
Core body temperature decreases, reducing metabolic damage
Physical activity increases, improving neuromuscular coordination and cognitive retention
Evidence from Studies
Supporting (1)
Community contributions welcome
Studies of aging in ames dwarf mice: Effects of caloric restriction
Contradicting (0)
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Gold Standard Evidence Needed
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