OLD MICE: Ames dwarf mice (above, right) outlive wild-type mice (above, left), but their life span is unresponsive to changes in dietary methionine levels.CHUCK KIMMERLE AT UNIVERSITY OF NORTH DAKOTA
The Paper H.M. Brown-Borg et al., “Growth hormone signaling is necessary for lifespan extension by dietary methionine,” Aging Cell, 13:1019-27, 2014. The paradox Genetic defects in growth-hormone (GH) signaling extend life span in mice, as do diets minimizing the intake of a single amino acid, methionine. Yet scientists had previously observed that the Ames dwarf mouse, deficient in GH, lives longer but has upregulated methionine metabolism. Holly Brown-Borg of the University of North Dakota and her colleagues thus decided to examine how GH genetics and dietary methionine might interact to impact life span. The diet Brown-Borg’s team compared four groups of mice on three different diets. Ames dwarf mice, GH-receptor knockout mice, transgenic mice that overexpressed GH, and wild-type controls were fed a diet with ...
