Effects of dietary sucrose on age-related changes in VLDL-triglyceride kinetics in the rat

The effects of sucrose feeding on in vivo kinetics of triglyceride metabolism were compared in rats aged 2 and 12 months. Sucrose was supplied as a 10% solution in their drinking water for 2 weeks. Although plasma triglyceride concentrations doubled with age, total triglyceride secretion rates for the whole rat (mg/min/rat) increased by 40%, suggesting a decrease in the efficiency of triglyceride removal from plasma with aging. The rate of triglyceride secretion per unit body mass (mg/min/kg body weight), however, decreased by 40% as the rats grew to 12 months of age. These age-related differences were statistically significant only in rats receiving supplementary sucrose. Feeding sucrose to rats of both ages doubled the secretion rates of triglyceride not only for the whole rat but also per unit body mass. However, it tripled triglyceride concentrations, implying that the sugar decreases the removal efficiency of plasma triglyceride equally in rats at either age. Fasting hypertriglyceridemia induced by sucrose supplement was much greater in old rats than in young rats (162 +/- 30 vs. 80 +/- 8 mg/dl). The present studies demonstrate that dietary sucrose enhances age-related changes in triglyceride kinetics in the rat.