Now, what exactly is this process of reciprocal regulation and how does it actually take place? So let's begin by imagining that our body is either exercising or our body is fasting. In either case, the blood glucose levels in our body will decrease. And when our blood concentration of glucose basically decreases what that means is our liver cells will begin to break down glycogen to glucose and release that glucose into the blood and that will help maintain a correct concentration of glucose in our blood. At the same time, for instance, if we're exercising our skeletal muscles will begin to break down glycogen to glucose and use that glucose to form the energy ATP molecules needed to carry out the proper voluntary motions that are required for that particular exercise. So basically during these circumstances our body wants to break down glycogen to glucose but at the same time it wants to stop the process of the synthesis of glycogen glycogenesis.