Muscle Glycogen Content and Lactate Uptake in Exercising Muscles

Abstract

Lactate, although an end product of anaerobic glycolysis, is also a substrate for oxidative metabolism. Thus, it is well-known that lactate is taken up and oxidized by the myocardium at a rate proportional to the level in the blood [1]. It has also been demonstrated that lactate is taken up [2] and oxidized [3] by working skeletal muscle. In this regard, lactate is a suitable substrate since it can readily enter the cell and the aerobic pathways with minimum of molecular modification. An unanswered question is if the uptake of lactate may be influenced by the availability of glycogen in the working muscle. Thus, the purpose of the present study was to examine the relationship between the relative production end uptake of lactate by human skeletal muscle during exercise at different glycogen levels of the skeletal muscle.