Abstract des Autors

The aim of the study was to determine the effect of feeding rats a low-calorie diet (30% of dietary requirements) for one month on their work capacity, and to estimate the utilisation of carbohydrate and lipid sources in sedentary and endurance-trained rats subjected to an exhausting exercise. The following variables were studied: hepatic and muscular glycogen, peripheral concentrations of glucose, triacylglycerols (TG) and free fatty acids (FFA) and the activities of citrate synthase (CS), lactate dehydrogenase (LDH) and beta-hydroxyacyl-CoA dehydrogenase (beta-OAC) in red and white fibers of the gastrocnemius muscle. The prolonged malnutrition strongly activated carbohydrate metabolism resulting in a reduction of carbohydrate stores and in a functional hypoglycaemia. The rate of basic metabolism was decreased, as indicated by lowered activities of LDH, CS and beta-OAC. Malnutrition activated preferentially the anaerobic processes in white fibers, while in the red ones mainly the aerobic pathways were impaired. Physical training prevented, to some degree, the unfavourable influence of malnutrition (preservation of muscle glycogen stores and inhibition of hypoglycaemia) and considerably increased the work capacity in rats. This suggests that energy for work was derived probably from FFA synthesis from extra-lipid sources. Verf.-Referat