So this is what we mean by a reciprocal pathway. One of them is turned off or one of them is turned on, but the other one is turned off. So when we're fasting or when we're exercising, the blood glucose levels are low. And in this particular case, we're going to basically initiate a signal transduction pathway that activates PKA. And it's the PKA that is responsible for actually initiating the breakdown of glycogen and at the same time stopping or turning off glycogen synthesis. Now, let's suppose our body is at rest or our body just ate a meal that is rich in carbohydrate molecules.