Reduced Organ Growth When Hyperphagia Is Prevented in Genetically Obese (fa/fa) Zucker Rats (41224)

Restricting the food intake of the genetically obese rat throughout life to that eaten by its lean littermate normalized body weight but not body composition compared to lean controls at 15 weeks of age. However, by 33 weeks of age the body weights of the restricted fatties were greater than those of lean controls but less than those of ad libitum-fed fatties. The weights of muscle, kidney, liver, and brain were decreased in restricted fatties. For the muscle and kidney significant decreases in DNA and protein content occurred in restricted fatties in comparison with both ad libitum-fed lean or obese controls. In the brain and liver more subtle but significant growth alterations were noted. Consequently, the ability of the calorically restricted obese rat to maintain its obese body composition occurs at the expense of normal growth in other organs and tissues.