Two paths of glucose utilization during heavy exercise in the dog

Abstract

The system of integrative glycemiometry (group of equations of blood glucose curves) describes the interplay of 3 variables: glucose infusion rate, blood glucose increment, and length of infusion time. It analyzes quantitatively multiple components of blood glucose disposal. Resting dogs were compared with those running on a treadmill at 4 levels of hyper-glycemia. All principal phenomena, found formerly at rest, were also identified during exercise including the initial phasic changes (analogous to the Staub-Traugott phenomenon) and subsequent inhibition of utilization, point of saturation with glucose, and simple glucose non-utilization model. At the point of saturation with glucose 2 chief activities meet in an integrative action during heavy exercise: one catabolizes glucose at a high rate of some 55 g/m2 per hr. i. e., 2.7 g/kg per hr., with priority in glucose uptake being given to the contracting tissues, though sometimes only after a time lag. The other activity also operating under the same factors as during rest is concerned with anabolizing glucose into storage substances at a maximum rate, not lower than at rest, in the order of some 67 g/m2 per hr., i. e., 3.2 g/kg per hr. Therefore, heavy exercise does not interfere with the maximum formation of glycogen and fat from glucose. The present work proves that there are 2 modes of increased glucose utilization and both work additively.