Mobilization rates of amino acids, fatty acids and carbohydrates during experimental diet induced Kwashiorkor and Obese conditions in rats

Abstract

Rats have been used extensively as animal models for the study of metabolic disorders such as in obesity and kwashiorkor. Previous studies using animal models have revealed that there are certain disorders in energy metabolism which are associated with obesity and kwashiorkor syndromes. This study was designed to explore further these metabolic defects by following the changes in activities of key regulatory enzymes involved in the energy generation pathways. Obesity and kwashiorkor are malnutrition states brought about by taking in of diets which have inadequate amounts or wrong proportions of certain nutrients. Kwashiorkor develops when the body is deprived of proteins but supplied with enough energy whereas obesity develops as a result of taking in more energy in the food than is expended in the activities of daily life. Obesity and Kwashiorkor syndromes were induced in 21 day old weanling rats by feeding them on high calorie, high protein diet and high calorie low protein diet respectively. The diets had enough vitamins and minerals. The control rats- were fed on a balanced diet of commercial rat pellets. All groups were allowed free access to food and water for 3 weeks and their weight was t;aken weekly. The activities of the key regulatory enzymes involved in carbohydrate, fatty acid and amino acid metabolism were measured in the liver, the heart and in the leg muscle homogenates. The levels of some metabolites namely lactate, pyruvate glucose and glycogen were also determined in the homogenates. The effects of malnutrition states (obesity and kwashiorkor) on by obese and least in the control rats. The respiratory control ratio of the mitochondriaisolated from obese and Kwashiorkor rat liver was less than that of the control animals. These results indicate that the mitochondria from obese and Kwashiorkor rats are not as efficient in producing energy when compared to the control animals. Taken together the results indicated that: (i) The Kwashiorkor rats are able to make up for their inability to produce ATP from oxidative phosphorylation by accelerating the glycolytic flux and fatty acid breakdown. (ii) The metabolism in obese rats is diverted toward energy storage as evidenced by the increased fatty acid synthesis and elevated activities of the enzymes involved in the lipogenesis. (iii) The inefficiency of the mitochondria to oxi~ize the substrates as a result of malnutrition leads to energy production using other pathways mainly glycolysis.