Abstract

As a mechanism for maintaining blood glucose homeostasis, the glucose-alanine cycle, which links the liver and skeletal muscles via blood circulation, is available. Previous studies report that during a short fasting period, the glucose-alanine cycle comes into operation, and glyconeogenesis occurs. The authors previously carried out studies on glyconeogenesis during and after exercise, using athletes. The present results obtained from fasting, quietly resting athletes and nonathletes were the same as those obtained in the previous studies. Furthermore, there was no difference between the glyconeogenesis occurring in athletes and in nonathletes. In order to further clarify the nature of glyconeogenesis in athletes and nonathletes, we orally administered 25 grams of L-alpha-alanine to resting athletes and nonathletes after an overnight 13 to 14 hour fast. The metabolisms of alanine, glucose, and fats were studied for three hours after the administration of alanine. The results suggest the following. An oral administration of 25 g L-alpha-alanine: 1) stimulted the glucose-alanine cycle in both athletes and nonathletes under fasting conditions, and the body tried to maintain blood glucose homeostasis. The effect becomes pronounced in athletes 120 min after administration; 2) inhibited the lipolysis in fat cells in both athletic and nonathletic subjects and reduced the supply of FFA to the body as an energy substrate. Verf.-Referat