Β-Hydroxybutyric acid

Β-Hydroxybutyric acid (also known as 3-hydroxybutyric acid or 3HB) is a organic compound that plays a significant role in the human body. It is a ketone body, which are water-soluble molecules produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, or in untreated (or inadequately treated) type 1 diabetes mellitus.

Chemistry

Β-Hydroxybutyric acid is a chiral compound with two enantiomers: D-3-hydroxybutyric acid and L-3-hydroxybutyric acid. The D-isomer is the biologically active form that is endogenously produced by humans and used as an energy source.

Biosynthesis

Β-Hydroxybutyric acid is synthesized in the liver from acetyl-CoA in a reaction catalyzed by the enzyme beta-hydroxybutyrate dehydrogenase. This process occurs when glucose levels are low, such as during fasting or starvation, and is part of the ketosis metabolic pathway.

Role in the body

Β-Hydroxybutyric acid serves as a source of energy for the brain, heart, and muscles during periods of fasting or starvation. It can cross the blood-brain barrier and is converted into acetyl-CoA, which is then used in the citric acid cycle to generate ATP, the body's main energy currency.

Clinical significance

Β-Hydroxybutyric acid is used as a diagnostic marker in the detection of ketoacidosis, a serious complication of diabetes. High levels of β-hydroxybutyric acid in the blood can lead to a decrease in blood pH, resulting in acidosis.

See also

• Ketone bodies
• Ketosis
• Ketoacidosis
• Acetyl-CoA
• Citric acid cycle