Lipoprotein status in Sprague-Dawley and LA/N-corpulent rats as affected by dietary carbohydrates

1. To compare the impact of type of carbohydrate, genotype and phenotype on the synthesis and levels of plasma lipoprotein protein. Sprague-Dawley rats and carbohydrate-sensitive LA/N-corpulent (cp) rats were fasted (2 days) and then fed diets containing 54% carbohydrate as either sucrose, fructose or cooked cornstarch for 2 days. 2. The amount of 3H-protein present in the VLDL + chylomicron fraction of Sprague-Dawley rats 2 hr after injection of 3H-leucine was affected by type of dietary carbohydrate: sucrose greater than fructose greater than starch. 3. Obese and lean LA/N-cp rats fed diets containing sucrose or fructose had lower concentrations of HDL protein and higher levels of 3H-protein in VLDL + chylomicron fraction than those fed starch. 4. Obese LA/N-cp rats had more HDL protein and higher levels of 3H-protein in VLDL + chylomicron fraction than their lean littermates.