ketogeneza

Ketogeneza is a metabolic process that occurs in the liver. It is the biochemical pathway during which excess acetyl-CoA is converted into ketone bodies. These ketone bodies, primarily acetoacetate, beta-hydroxybutyrate, and acetone, are then released into the bloodstream and can be used as an alternative fuel source by various tissues, particularly the brain and muscles, when glucose availability is limited.

The production of ketone bodies is stimulated by low carbohydrate intake, prolonged fasting, or starvation. During these states, the body's glycogen stores are depleted, and the body begins to break down stored fats for energy. Fatty acids are transported to the liver, where they undergo beta-oxidation to produce acetyl-CoA. Normally, acetyl-CoA enters the citric acid cycle for energy production. However, when the rate of fatty acid breakdown exceeds the capacity of the citric acid cycle, or when carbohydrate availability is low, acetyl-CoA is shunted into the ketogenesis pathway.

Ketone bodies are water-soluble and can readily cross cell membranes. They are particularly important for the brain, which relies heavily on glucose under normal conditions but can adapt to utilize ketone bodies for up to 70% of its energy needs during prolonged periods of low glucose. The production of ketone bodies is a survival mechanism that allows the body to conserve glucose and maintain vital functions when food is scarce. While beneficial in certain circumstances, excessive ketone body production can lead to ketoacidosis, a dangerous condition characterized by a significant drop in blood pH.