EFFECT OF INCREASED METABOLISM AND OF HYPERPHAGIA ON DIETARY AMINO ACID IMBALANCE IN THE RAT

Abstract

In male Wistar rats, the effects of cold exposure (6 °C) on dietary amino acid imbalances were investigated. In agreement with the previous observation of Klain et al., exposure to cold throughout the experimental period (28 days) prevented the decreased food intake and body weight gain observed at 24 °C in rats fed a 6% fibrin diet supplemented with 0.4% DL-methionine and 0.6% DL-phenylalanine. It was also observed that subsequent exposure to cold eliminated these effects of an existing- imbalance previously induced at: 24 °C. With a 10% fibrin diet supplemented with 0.6% DL-methionine and 0.9% DL-phenylalanine, no pronounced effect attributable to an amino acid imbalance was observed at 24 °C. It is concluded that exposure to cold prevents the deleterious effects of an amino acid imbalance superimposed on a 6% protein diet, and subsequent exposure to cold eliminates these effects of an existing imbalance, L-Thyroxine, injected daily at a level of 30 μg/100 g body weight, simulated cold exposure in that it caused an increased food intake in rats fed a 6% fibrin – unbalanced diet. In hypothalamic-hyperphagic rats, a deleterious effect of a 6% fibrin – imbalanced diet was apparent initially; after 10 days' feeding, lesioned rats fed a 6% fibrin diet ceased to gain weight whereas those fed the imbalanced diet continued to do so.