So cells such as cardiac muscle cells have special membrane proteins that can make the cell highly permeable to lactate. And once inside the cardiac myosides, the lactate can be transformed back into Pyruvate by lactate dehydrogenase and then fed into the citric acid cycle to generate ATP. Why? Well, because in cardiac muscle cells we only use aerobic respiration, never anaerobic respiration. There's always plenty of oxygen inside these cells and this helps these cardiac muscle cells obtain an additional source of energy and also helps conserve the glucose in the blood so that other cells can actually use the glucose, for instance, brain cells. Now the second place where these lactate molecules end up is the liver cells.