THE EFFECT OF LOW GLYCOGEN CONTENT ON THE FATIGUE CURVE AND ON LACTIC ACID FORMATION IN EXCISED MUSCLE

Abstract

Large bullfrogs after idiopathic or insulin convulsions were killed as were a group of normal frogs. The muscles of the thigh and the gastrocnemius on one side were used as controls, while the thigh muscles of the other leg were put into chloroform rigor and the isolated gastrocnemius fatigued by induction shocks. All the muscles were analyzed for glycogen, lactic acid, free carbohydrate and P. Normal muscles, when stimulated or made to pass into chloroform rigor, showed a loss of glycogen exactly balanced by a gain in lactic acid. The muscles from frogs suffering from idiopathic or insulin convulsions had a very low content of glycogen. When fatigued or made to pass into rigor, their loss of glycogen and increase in lactic acid were slight, the latter being greater than the former. This excess was not due to changes in free carbohydrate or P content of muscle. These isolated muscles with little or no glyeogen still contracted upon stimulation, giving a normal fatigue curve.