Three chemical compounds: 3-oxobutanoic acid (acetoacetic acid), 3-hydroxybutanoic acid (β-hydroxybutyric acid), and propanone (acetone). When present in the blood in high concentrations, they increase the blood's acidity. Known as ketosis, this condition occurs in starvation and diabetes mellitus. The ketone bodies are products of poor carbohydrate metabolism, and they accumulate in the body tissue and fluids, especially the urine. Note that β-hydroxybutyrate is not chemically a ketone; however, it is considered to be physiologically equivalent to one because it and acetoacetate are readily interconverted in the body.
