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How do hormones help maintain stable blood glucose levels after eating and during fasting?

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Diagram explaining ATP's role in powering cellular activities, with arrows showing ATP produced by mitochondria, chloroplasts, and glycolysis, and used for making biomolecules, transporting substances, and driving energy-requiring processes; includes a structural diagram of ATP with labeled adenine, ribose, and phosphate groups. — Physiology Adenosine triphosphate (ATP) is the power source of many biochemical reactions. It is produced in the cell structures and system listed at the left to energize the important life processes listed on the right. An abbreviated chemical formula of the structure of ATP is also shown. The two high-energy P―O―P bonds are responsible for its power.

The body maintains stable blood glucose levels through a precise hormonal feedback system involving the pancreas, which ensures glucose is stored when abundant and mobilized when needed.12

The Fed State

After eating, the digestion of carbohydrates increases blood glucose concentrations. This triggers the islets of Langerhans to secrete insulin. Insulin acts to lower blood glucose by:1
* Stimulating the uptake of glucose into liver, muscle, and adipose tissue.12
* Inhibiting the liver from releasing stored glucose.12
* Promoting the storage of nutrients, including the conversion of glucose into glycogen.13

The Fasting State

As time passes after a meal, blood glucose levels decrease, leading to a reduction in insulin secretion and an increase in the secretion of glucagon by alpha cells. Glucagon works to raise blood glucose by:134
* Stimulating glycogenolysis, the breakdown of stored glycogen into glucose in the liver.34
* Promoting gluconeogenesis, the production of new glucose from non-carbohydrate sources like amino acids and glycerol.14

Together, these hormones ensure that the brain and other tissues have a consistent energy supply, maintaining homeostasis regardless of food intake.12