Effect of dietary sucrose and genotype on metabolic parameters of a new strain of genetically obese rat: LA/N-corpulent

Abstract

A new strain of genetically obese rat, LA/N-corpulent ( cp) was studied. Homozygous ( cp/cp) corpulent and heterozygous ( cp/+) and homozygous ( +/+) lean young male rats were fed for 4 weeks diets containing 54% carbohydrate as either sucrose or starch. A genotype effect between corpulent and lean rats (corpulent > lean) was observed with food intake, weight gain, total fat pad weight and size, liver weight and size, activities of liver lipogenic enzymes, fasting levels of serum triglyceride, free fatty acid, total cholesterol and insulin, and response levels of serum insulin and glucose. Levels of insulin and triglyceride were 6 to 8 times greater in corpulent than lean rats. The magnitude of metabolic responses in lean rats was similar except for total fat pad weight and size which was greater in cp/+ than +/+ rats. A sucrose effect (sucrose > starch) was observed with weight gain, total fat pad weight and size, liver weight and size, activities of liver lipogenic enzymes, fasting level of serum triglyceride and response levels of serum insulin and glucose. The data demonstrate that corpulent ( cp/cp) rats have metabolic characteristics similar to type IV hyperlipoproteinemia in humans and that these characteristics are magnified by feeding of sucrose.