The formation of 2-hydroxybutyric acid in experimental animals.
1. The formation of 2-hydroxybutyric acid (2-HB) has been studied by animal experiments. 2. 2-HB was excreted in the urine together with lactic acid following intravenous administration of huge amounts of 3-hydroxybutyric acid (sodium salt) to a dog. 3. Rats made diabetic by an injection of streptozotocin were found to excrete large quantities of 2HB in the urine (up to 300 mumol/24 h) together with the development of ketoacidosis. 4. The use of 14-C-labelled precursors clearly showed that the amino acids methionine, threonine and homoserine can be converted to 2-HB. 5. 2-Aminobutyric acid is also converted to 2-HB, with 2-oxobutyric acid as an intermediate metabolite. The ratio between the urinary concentrations of 2-HB and 2-oxobutyric acid was increased by the ingestion of ethanol. 6. In normal rats neither a prolonged fasting period nor loading with large doses of methionine, threonine and homoserine resulted in the excretion of 2-HB. 7. The mechanisms behind the formation of 2-HB are discussed, and it is concluded that an increased NADH2/NAD ratio in the cytoplasma is the most important factor.
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D003920:Diabetes Mellitus / Q000139:chemically induced / Q000378:metabolism; D004285:Dogs; D006885:Hydroxybutyrates / Q000096:biosynthesis* / Q000652:urine; D007773:Lactates / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D051381:Rats; D013311:Streptozocin
D000596:Amino Acids; D006885:Hydroxybutyrates; D007773:Lactates; D009243:NAD; D013311:Streptozocin