What helps certain mice to live so much longer than other mice?
Some research suggests lacking growth hormone allows them to live so long. A lack of growth hormone means there is no demand to make protein and turn amino acid into muscle; this frees the mice, metabolically, to fight off internal and external stresses.
I have read some material that suggests we concentrate our attention to methionine metabolism. This essential amino acid is critical for protein synthesis and growth, and is also integral to metabolism. Also Glutathione, an important antioxidant, is generated by the methionine (MET) pathway. Glutathione is made up of three amino acids, the key one in these studies is cysteine. The essential amino acids, MET and cysteine, can be easily modified in the diet.
Certain mice have highly active methionine metabolism but when they are given growth hormone, this activity goes down. Methionine metabolism is regulated by growth hormone.
Calorie restriction (CR) is well known to extend lifespan in multiple species. It has also been shown that restricting MET intake (without CR) extends the lifespan of rats and mice. There are similarities in mice subjected to CR and the dwarf mice which suggests there are common underlying factors that lead to slower aging.
The mechanisms leading to this potential `slower’ aging and lifespan extension are unknown.