The degradation of glycogen during fasting or exercise and the synthesis of glycogen during the fed state are regulated by different mechanisms to maintain glucose homeostasis in the body. These processes are mainly regulated by hormones and allosteric effectors.1. Glycogen degradation glycogenolysis during fasting or exercise:During fasting or exercise, the body needs to produce glucose to meet its energy demands. Glycogen stored in the liver and muscles is broken down into glucose through the process of glycogenolysis. The regulatory mechanisms involved in glycogen degradation are:a Hormonal regulation: The primary hormones involved in glycogenolysis are glucagon and epinephrine adrenaline . Glucagon is secreted by the pancreas in response to low blood glucose levels during fasting, while epinephrine is released by the adrenal glands during exercise or stress. Both hormones activate glycogen phosphorylase, the enzyme responsible for breaking down glycogen into glucose-1-phosphate.b Allosteric regulation: Glycogen phosphorylase is also regulated by allosteric effectors. High levels of AMP a signal of low energy activate glycogen phosphorylase, promoting glycogen degradation. In contrast, high levels of ATP and glucose-6-phosphate signals of high energy inhibit glycogen phosphorylase, preventing further glycogen breakdown.2. Glycogen synthesis glycogenesis during the fed state:During the fed state, excess glucose is converted into glycogen for storage in the liver and muscles through the process of glycogenesis. The regulatory mechanisms involved in glycogen synthesis are:a Hormonal regulation: Insulin is the primary hormone involved in glycogenesis. It is secreted by the pancreas in response to high blood glucose levels after a meal. Insulin promotes glycogen synthesis by activating glycogen synthase, the enzyme responsible for converting glucose into glycogen.b Allosteric regulation: Glycogen synthase is also regulated by allosteric effectors. High levels of glucose-6-phosphate a signal of high glucose availability activate glycogen synthase, promoting glycogen synthesis. In contrast, high levels of AMP a signal of low energy inhibit glycogen synthase, preventing further glycogen synthesis.In summary, the degradation of glycogen during fasting or exercise is primarily regulated by glucagon, epinephrine, and allosteric effectors such as AMP, while the synthesis of glycogen during the fed state is mainly regulated by insulin and allosteric effectors such as glucose-6-phosphate. These different regulatory mechanisms ensure that glycogen is broken down when the body needs energy and is synthesized when there is excess glucose available.