Changes of aging parameters among rats on diets differing in fat quantity and quality

Portion rats in a life span study were fed three diets which differed in the quantity and quality of total fats but were supplied in calorically equal amounts. In an attempt to comparing aging rates, we used a combination of tests involving different organ systems. This holistic approach to measuring aging included the assessment of changes in multifactorially regulated systems of glucose homeostasis and oxygen consumption; changes in tension responses of the extracellular protein collagen and accumulation of lipofuscin pigment in adrenal glands were also measured. Glucose tolerance and oxygen consumption changed in age largely as expected and there were no consistent differences between the aging rates for the three different diets. Accumulation of the intracellular aging pigment lipofuscin and the breaking time of tail tendons also showed the expected increases with increasing age. Dietary differences were noted with the 2-year-old rats consuming the low fat stock diet showing the greatest accumulation of lipofuscin and the longest tail tendon breaking times.