A cycle which occurs between the red blood cell, kidneys, muscle, platelets, and the liver and which helps maintain a normal blood glucose level in the face of changes in lactate production. Cori cycle activity is particularly important during exercise as the working muscle is unable to oxidize all the lactate it produces. The muscle does not have gluconeogenic activity. Thus, it must export the accumulating lactate via the blood to the liver, which in turn uses it to make glucose. Figure 14 illustrates this cycle.