Plasma glucose and the action of calorie restriction on aging.

We tested the hypothesis that retardation of aging by caloric restriction is due in part to decreased levels of plasma glucose over the life span. Male C57BL/6 mice expressing a human GLUT4 minigene (transgenic [TG] mice) and their nontransgenic littermates (NTG mice) were maintained under specific pathogen-free conditions. Mice were fed ad libitum (A mice) or 40% less than ad libitum (R mice) from age 6 weeks.