In studies where D-(-)-3-hydroxy[4,4,4-2H3]butyrate is employed as isotopic tracer in vivo, we have described a selected ion monitoring, gas-liquid chromatography-mass spectrometry micromethod which measures [2H3] tracer enrichment in 3-hydroxybutyrate and acetoacetate from 300-microliters blood samples. For plasma samples in the physiologic range, intra- and interassay precisions for each keto...

The capacity of foetal and neonatal liver to oxidize short-, medium- and long-chain fatty acids was studied in the guinea pig. Liver mitochondria from foetal and newborn animals were unable to synthesize ketone bodies from octanoate, but octanoylcarnitine and palmitoylcarnitine were readily ketogenic. The ketogenic capacity at 24 h after birth was as high as in adult animals. Hepatocytes isolat...

A gas chromatography-mass spectrometry (GC-MS) method for determination of ketone bodies (β-hydroxybutyrate, acetone, and acetoacetate) in blood is presented. The method is based on enzymatic oxidation of D-β-hydroxybutyrate to acetoacetate, followed by decarboxylation to acetone, which was quantified by the use of headspace GC-MS using acetone-(13)C(3) as an internal standard. The developed me...

BACKGROUND The ketogenic diet (KD) is a very low-carbohydrate, high-fat and adequate-protein diet with no calorie limit that induces a metabolic condition called "physiological ketosis". It was first introduced to treat epilepsy in the 1920s and has become quite popular recently as weight-loss and performance-enhancing diet. Its therapeutic use in a range of diseases is under investigation. Dur...

BACKGROUND In conscious humans, reduction in hemoglobin concentration to 5 g/dl did not produce inadequate systemic oxygenation. However, systemic measures of inadequate oxygenation may not be sufficiently sensitive to detect inadequate oxygenation in individual organs such as splanchnic organs. The authors tested the hypothesis that acute normovolemic anemia to hemoglobin less than 6.0 g/dl in...

Even in the absence of food intake, several animal species recovering from physical activity of high intensity can replenish completely their muscle glycogen stores. In some species of mammals, such as in rats and humans, glycogen repletion is only partial, thus suggesting that a few consecutive bouts of high-intensity exercise might eventually lead to the sustained depletion of their muscle gl...

Octanoic and decanoic acid, the major constituents of the Medium Chain Triglyceride (MCT) Emulsion diet, have been detected in appreciable quantities in the peripheral blood of children with intractable seizures treated with the MCT diet. Serum concentrations of these acids as well as beta hydroxybutyrate and acetoacetate rose as the diet was introduced and on full diet showed pronounced diurna...

D-(-)-3-Hydroxybutyrate (DHB), the immediate depolymerization product of the intracellular carbon store poly-3-hydroxybutyrate (PHB), is oxidized by the enzyme 3-hydroxybutyrate dehydrogenase to acetoacetate (AA) in the PHB degradation pathway. Externally supplied DHB can serve as a sole source of carbon and energy to support the growth of Sinorhizobium meliloti. In contrast, wild-type S. melil...

A rapid and reproducible method for the assay of 14C radioactivity in ketone bodies is described, based on the heat lability of acetoacetate and the ability of beta-hydroxybutyrate to quantitatively bind to and elute from an ion exchange resin. Potential interference from 14C activity in the ketone body metabolites (CO2, bicarbonate and acetone) during infusion of 14C-labeled ketone bodies is e...

We investigated the effect of pre- "race" ingestion of a 1,3-butanediol acetoacetate diester on blood ketone concentration, substrate metabolism and performance of a cycling time trial (TT) in professional cyclists. In a randomized cross-over design, 10 elite male cyclists completed a ~31 km laboratory-based TT on a cycling ergometer programmed to simulate the 2017 World Road Cycling Championsh...