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Biomolecules Oct 2022Beta-hydroxybutyrate (βOHB), along with acetoacetate and acetone, are liver-produced ketone bodies that are increased after fasting or prolonged exercise as an...
Beta-hydroxybutyrate (βOHB), along with acetoacetate and acetone, are liver-produced ketone bodies that are increased after fasting or prolonged exercise as an alternative fuel source to glucose. βOHB, as the main circulating ketone body, is not only a G-protein coupled receptor ligand but also a histone deacetylases inhibitor, prompting the reexamination of its role in health and disease. In this study, we compared the effects of two commercial βOHB formulations an enantiomer R βOHB and a racemic mixture ±βOHB on induced pluripotent stem cell cardiac myocytes (iPS-CMs) electrophysiology. Cardiac myocytes were cultured in R βOHB or ±βOHB for at least ten days after lactate selection. Flouvolt or Fluo-4 was used to assay iPS-CMs electrophysiology. We found that while both formulations increased the optical potential amplitude, R βOHB prolonged the action potential duration but ±βOHB shortened the action potential duration. Moreover, ±βOHB increased the peak calcium transient but R βOHB reduced the peak calcium transient. Co-culturing with glucose or fatty acids did not ameliorate the effects, suggesting that βOHB was more than a fuel source. The effect of βOHB on iPS-CMs electrophysiology is most likely stereoselective, and care must be taken to evaluate the role of exogenous βOHB in health and disease.
Topics: 3-Hydroxybutyric Acid; Myocytes, Cardiac; Acetoacetates; Calcium; Acetone; Ligands; Ketone Bodies; Glucose; Histone Deacetylases; Receptors, G-Protein-Coupled; Lactates; Electrophysiology
PubMed: 36291708
DOI: 10.3390/biom12101500 -
The Journal of Clinical Investigation Oct 1973The metabolic and kinetic responses to rapidly intravenously administered sodium acetoacetate (1.0 mmol/kg body wt) was studied after an overnight fast in 12 male and...
The metabolic and kinetic responses to rapidly intravenously administered sodium acetoacetate (1.0 mmol/kg body wt) was studied after an overnight fast in 12 male and female adults weighing between 88 and 215% of average body weight. Blood was obtained before, during, and after the infusion for determination of circulating concentrations of immunoreactive insulin, glucose, acetoacetate, beta-hydroxybutyrate and free fatty acids. In three obese subjects the studies were repeated after 3 and 24 days of total starvation. After the overnight fast acetoacetate rose rapidly reaching a peak concentration at the end of the infusion; beta-hydroxybutyrate concentrations also increased rapidly and exceeded those of acetoacetate 10 min postinfusion. Total ketone body concentration at the end of the infusion period was comparable to that found after prolonged starvation. After the initial mixing period, acetoacetate, beta-hydroxybutyrate and total ketone bodies rapidly declined in a parallel manner. There were no obvious differences between the subjects with regard to their blood concentrations of ketone bodies. The mean plasma free fatty acid concentration decreased significantly during the 20th to 90th min postinfusion period; for example the control concentration of 0.61 mmol/liter fell to 0.43 mmol/liter at 60 min. In the three obese subjects studied repeatedly, fasting plasma free fatty acids decreased with acetoacetate infusion from 0.92 to 0.46 mmol/liter after the 3 day fast and from 1.49 to 0.71 mmol/liter after the 24 day fast. Acetoacetate infusion caused no changes in blood glucose concentration after an overnight fast. However, in the three obese subjects restudied after 3- and 24-day fasts blood glucose decreased, respectively, from 3.49 to 3.22 mmol/liter and from 4.07 to 3.49 mmol/liter. The mean serum insulin concentration in all subjects significantly increased from 21 to 46 muU/ml at the completion of the infusion and rapidly declined. In the three obese subjects restudied after 3- and 24-day fasts an approximate two-fold increase of serum insulin was observed after each acetoacetate infusion. The mean fractional utilization rate of exogenously derived ketone bodies for all 12 subjects after an overnight fast was 2.9% min(-1). In the three obese subjects studied after an overnight, 3 and 24 day fast the mean fractional utilization rates were 2.1%, 1.5%, and 0.6% min(-1), respectively. Ketone body volumes of distribution in the overnight fasted subjected varied from about 18% to 31% of body wt, suggesting that ketone bodies are not homogenously distributed in the body water. In the three obese subjects restudied after 3- and 24-day fasts volumes of distribution remained approximately constant. When total ketone body concentrations in the blood were below 2.0 mmol/liter, there was a linear relationship between ketone body utilization rates and ketone body concentrations; no correlation was found when blood concentrations were higher.
Topics: Acetoacetates; Adult; Antigens; Blood Glucose; Fatty Acids, Nonesterified; Female; Humans; Hydroxybutyrates; Infusions, Parenteral; Insulin; Ketone Bodies; Kinetics; Male; Middle Aged; Starvation; Time Factors
PubMed: 4729054
DOI: 10.1172/JCI107453 -
Cell Chemical Biology Aug 2017The α-oxoaldehyde methylglyoxal is a ubiquitous and highly reactive metabolite known to be involved in aging- and diabetes-related diseases. If not detoxified by the...
The α-oxoaldehyde methylglyoxal is a ubiquitous and highly reactive metabolite known to be involved in aging- and diabetes-related diseases. If not detoxified by the endogenous glyoxalase system, it exerts its detrimental effects primarily by reacting with biopolymers such as DNA and proteins. We now demonstrate that during ketosis, another metabolic route is operative via direct non-enzymatic aldol reaction between methylglyoxal and the ketone body acetoacetate, leading to 3-hydroxyhexane-2,5-dione. This novel metabolite is present at a concentration of 10%-20% of the methylglyoxal level in the blood of insulin-starved patients. By employing a metabolite-alkyne-tagging strategy it is clarified that 3-hydroxyhexane-2,5-dione is further metabolized to non-glycating species in human blood. The discovery represents a new direction within non-enzymatic metabolism and within the use of alkyne-tagging for metabolism studies and it revitalizes acetoacetate as a competent endogenous carbon nucleophile.
Topics: Acetoacetates; Alkynes; Amino Acid Sequence; Chromatography, High Pressure Liquid; Diabetes Mellitus; Hexanones; Humans; Ketone Bodies; Mass Spectrometry; Pyruvaldehyde; Serum Albumin
PubMed: 28820963
DOI: 10.1016/j.chembiol.2017.07.012 -
American Journal of Physiology. Heart... Apr 2003Blunted beta-adrenergic inotropism in stunned myocardium is restored by pharmacological (N-acetylcysteine) and metabolic (pyruvate) antioxidants. The ketone body...
Blunted beta-adrenergic inotropism in stunned myocardium is restored by pharmacological (N-acetylcysteine) and metabolic (pyruvate) antioxidants. The ketone body acetoacetate is a natural myocardial fuel and antioxidant that improves contractile function of prooxidant-injured myocardium. The impact of acetoacetate on postischemic cardiac function and beta-adrenergic signaling has never been reported. To test the hypothesis that acetoacetate restores contractile performance and beta-adrenergic inotropism of stunned myocardium, postischemic Krebs-Henseleit-perfused guinea pig hearts were treated with 5 mM acetoacetate and/or 2 nM isoproterenol at 15-45 and 30-45 min of reperfusion, respectively, while cardiac power was monitored. The myocardium was snap frozen, and its energy state was assessed from phosphocreatine phosphorylation potential. Antioxidant defenses were assessed from GSH/GSSG and NADPH/NADP(+) redox potentials. Stunning lowered cardiac power and GSH redox potential by 90 and 70%, respectively. Given separately, acetoacetate and isoproterenol each increased power and GSH redox potential three- to fivefold. Phosphocreatine potential was 70% higher in acetoacetate- vs. isoproterenol-treated hearts (P < 0.01). In combination, acetoacetate and isoproterenol synergistically increased power and GSH redox potential 16- and 7-fold, respectively, doubled NADPH redox potential, and increased cAMP content 30%. The combination increased cardiac power four- to sixfold vs. the individual treatments without a coincident increase in phosphorylation potential. Potentiation of isoproterenol's inotropic actions endured even after acetoacetate was discontinued and GSH potential waned, indicating that temporary enhancement of redox potential persistently restored beta-adrenergic mechanisms. Thus acetoacetate increased contractile performance and potentiated beta-adrenergic inotropism in stunned myocardium without increasing energy reserves, suggesting its antioxidant character is central to its beneficial actions.
Topics: Acetoacetates; Adrenergic beta-Agonists; Animals; Antioxidants; Blood Pressure; Citric Acid; Cyclic AMP; Drug Synergism; Energy Metabolism; Glucose-6-Phosphate; Glutathione; Guinea Pigs; Heart Rate; Isoproterenol; Kinetics; Male; Muscle Contraction; Myocardial Stunning; Myocardium; NADP; Oxidation-Reduction; Phosphorylation; Receptors, Adrenergic, beta; Ventricular Function, Left
PubMed: 12595283
DOI: 10.1152/ajpheart.00473.2002 -
The Journal of Clinical Investigation Oct 1970Ketonuria has been observed in alcoholics. To study the mechanism of this effect, healthy, volunteers were given adequate diets (36% of calories as lipid and 15% as...
Ketonuria has been observed in alcoholics. To study the mechanism of this effect, healthy, volunteers were given adequate diets (36% of calories as lipid and 15% as protein) for 18 days, with isocaloric replacement of carbohydrate (46% of calories) by either ethanol or additional fat. The latter resulted in a high fat diet, with 82% of calories as lipid. After about 1 wk of alcohol, massive and persistent ketonuria developed. Compared with the control period, there was a 30-fold increase in fasting blood acetoacetate and beta-hydroxybutyrate (P < 0.001). With the high fat diet, acetoacetate and beta-hydroxybutyrate increased 8- to 10-fold (P < 0.001). In the postprandial state, ethanol also induced hyperketonemia, but less markedly than when ethanol followed an overnight fast. With low fat diets (5% of calories), alcohol (46% of total calories) did not induce ketonuria or hyperketonemia, suggesting that a combination of alcohol and dietary fat is necessary. The addition of alcohol to rat liver slices did not affect ketogenesis. In rats pretreated with alcohol for 3 days, however, ketonemia developed, hepatic glycogen was decreased, and liver slices (incubated with palmitate-(14)C and glucose) had a significant increase in acetoacetate production, when compared to carbohydrate pretreated controls. Alcohol pretreatment or addition of alcohol in vitro had no effect on acetoacetate utilization by rat diaphragms, and decreased only slightly the conversion of beta-hydroxybutyrate-(14)C to (14)CO(2). Thus, the hyperketonemia and ketonuria observed after alcohol consumption cannot be attributed to an immediate effect of alcohol, but is the consequence of a delayed change in intermediary metabolism characterized by increased hepatic ketone production from fatty acids, possibly linked to ethanol-induced glycogen depletion and depression of citric acid cycle activity.
Topics: Acetoacetates; Adult; Animals; Diaphragm; Diet; Dietary Carbohydrates; Dietary Fats; Ethanol; Fasting; Female; Humans; Hydroxybutyrates; In Vitro Techniques; Ketones; Liver; Male; Middle Aged; Rats
PubMed: 5456793
DOI: 10.1172/JCI106395 -
The Journal of Clinical Investigation Mar 1971To clarify the role of insulin and growth hormone (HGH) in regulating substrate production for body fuel during prolonged starvation, 6 normal subjects and 10...
To clarify the role of insulin and growth hormone (HGH) in regulating substrate production for body fuel during prolonged starvation, 6 normal subjects and 10 HGH-deficient dwarfs were fasted for 6 days. Four of these dwarfs received HGH during the fast. Blood glucose concentration decreased a mean 15 mg/100 ml in both controls and HGH-treated dwarfs, but decreased 50 mg/100 ml in untreated dwarfs. The final level at which the blood glucose stabilized was significantly higher in the former two groups (65 +/-1.0 mg/100 ml and 88 +/-19 mg/100 ml, respectively, versus 39.0 +/-4.0 mg/100 ml in the untreated dwarfs). The decline in plasma insulin concentration showed a comparable pattern, decreasing from a similar basal level to 7.7 +/-0.4 muU/ml in controls, 8.8 +/-1.1 muU/ml in dwarfs treated with HGH, and to a significantly lower level of 3.8 +/-1.1 muU/ml in untreated dwarfs. When glucose concentrations were plotted against paired insulin values, the correlation in both dwarfs and normals was significant. In normals, no correlation existed at any time between plasma HGH levels and plasma concentration of either glucose or free fatty acid. Free fatty acid, beta-hydroxybutyrate, and acetoacetate increased respectively in normals to peak concentrations in plasma of 1.55 +/-0.11, 2.87 +/-0.23, and 0.77 +/-0.09 mmoles/liter. Untreated dwarfs had significantly greater values of all three (mean maximal concentration: FFA = 2.16 +/-0.17 mmoles/liter, beta-hydroxybutyrate = 4.11 +/-0.34 mmoles/liter, and acetoacetate = 1.16 +/-0.10 mmoles/liter). Values returned toward normal in HGH-treated dwarfs. The cahnges in plasma concentrations of beta-hydroxybutyrate and acetoacetate were not due to changes in renal excretion. In starvation, the relation between insulin on the one hand and glucose and free fatty acid on the other hand is maintained in the absence of HGH. However, the setting of blood glucose concentration at which this relation takes place is decreased in the absence of HGH. This results in a lower than normal insulin level and, consequently, in a higher than normal free fatty acid concentration.
Topics: Acetoacetates; Adult; Aged; Blood Glucose; Blood Urea Nitrogen; Body Height; Body Surface Area; Body Weight; Carbon Dioxide; Humans
PubMed: 5101781
DOI: 10.1172/JCI106527 -
Environmental Health and Preventive... Mar 2012The age-related effects of fasting on lipolysis, the production of ketone bodies, and plasma insulin levels were studied in male 3-, 8-, and 32-week-old Sprague-Dawley...
OBJECTIVE
The age-related effects of fasting on lipolysis, the production of ketone bodies, and plasma insulin levels were studied in male 3-, 8-, and 32-week-old Sprague-Dawley rats.
METHODS
The rats were divided into fasting and control groups. The 3-, 8- and 32-week-old rats tolerated fasting for 2, 5, and 12 days, respectively.
RESULTS
Fasting markedly reduced the weights of perirenal and periepididymal white adipose tissues in rats in the three age groups. The mean rates of reduction in both these adipose tissue weights during fasting periods were higher in the order of 3 > 8 > 32-week-old rats. Fasting transiently increased plasma free fatty acid (FFA), total ketone body, β-hydroxybutyrate, and acetoacetate concentrations in the rats in the three age groups. However, plasma FFA, total ketone body, β-hydroxybutyrate, and acetoacetate concentrations in the 3-week-old rats reached maximal peak within 2 days after the onset of fasting, although these concentrations in the 8- and 32-week-old rats took more than 2 days to reach the maximal peak. By contrast, the augmentation of plasma FFA, total ketone body, β-hydroxybutyrate, and acetoacetate concentrations in the rats in the three age groups had declined at the end of each experimental period. Thus, the capacity for fat mobilization was associated with tolerance to fasting. Plasma insulin concentrations in the rats in the three age groups were dramatically reduced during fasting periods, although basal levels of insulin were higher in the order of 32 > 8 > 3 week-old rats.
CONCLUSION
These results suggest that differences in fat metabolism patterns among rats in the three age groups during prolonged fasting were partly reflected the metabolic turnover rates, plasma insulin levels, and amounts of fat storage.
Topics: Acetoacetates; Adipose Tissue; Aging; Animals; Body Weight; Fasting; Fatty Acids, Nonesterified; Insulin; Ketone Bodies; Lipolysis; Male; Rats; Rats, Sprague-Dawley
PubMed: 21850422
DOI: 10.1007/s12199-011-0231-0 -
European Journal of Biochemistry Mar 1995The nitrate-reducing bacterial strain BunN is able to grow with acetone and nitrate under anoxic conditions. Dialyzed crude cell-free extracts of...
The nitrate-reducing bacterial strain BunN is able to grow with acetone and nitrate under anoxic conditions. Dialyzed crude cell-free extracts of acetone-plus-nitrate-grown cells of strain BunN catalyzed the exchange of 14CO2 into acetoacetate in an ADP-dependent reaction. The rates of exchange catalyzed by extracts of acetate-grown or 3-hydroxybutyrate-grown cells were only 13% of that catalyzed by extracts of acetone-grown cells. The activity was enzymic since it was destroyed by boiling and was proportional to the amount of added extract. The optimal acetoacetate concentration was 100 mM and the apparent Km was 11.1 mM. The pH optimum was 6.5, the exchange was not dependent on the addition of biotin, and the activity was not inhibited by avidin. The exchange activity was not stimulated (less than two fold) by a variety of metal ions or by a range of possible cofactors. Under optimal conditions (100 mM acetoacetate, 5 mM ADP, 10 mM NaHCO3, pH 6.5, under N2), the exchange activity was 2.7 nmol.min-1.mg protein-1; 2% of the in vivo carboxylation activity of acetone-plus-nitrate-grown cultures. It is suggested that the exchange reaction is a partial reaction catalyzed by the enzyme (or enzyme complex) that carboxylates acetone, and that the methods developed in this study provide a means with which to investigate this reaction further.
Topics: Acetoacetates; Acetone; Carbon Dioxide; Carbon Radioisotopes; Catalysis; Gram-Negative Bacteria; Nitrates
PubMed: 7737163
DOI: 10.1111/j.1432-1033.1995.0677m.x -
The Journal of Biological Chemistry Jan 2016Acetoacetate (AA) is a ketone body and acts as a fuel to supply energy for cellular activity of various tissues. Here, we uncovered a novel function of AA in promoting...
Acetoacetate (AA) is a ketone body and acts as a fuel to supply energy for cellular activity of various tissues. Here, we uncovered a novel function of AA in promoting muscle cell proliferation. Notably, the functional role of AA in regulating muscle cell function is further evidenced by its capability to accelerate muscle regeneration in normal mice, and it ameliorates muscular dystrophy in mdx mice. Mechanistically, our data from multiparameter analyses consistently support the notion that AA plays a non-metabolic role in regulating muscle cell function. Finally, we show that AA exerts its function through activation of the MEK1-ERK1/2-cyclin D1 pathway, revealing a novel mechanism in which AA serves as a signaling metabolite in mediating muscle cell function. Our findings highlight the profound functions of a small metabolite as signaling molecule in mammalian cells.
Topics: Acetoacetates; Animals; Cell Proliferation; Cyclin D1; Disease Models, Animal; Gene Expression Regulation; Ketone Bodies; MAP Kinase Kinase 1; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Mice, Inbred mdx; Muscle, Skeletal; Muscular Dystrophy, Animal; Regeneration; Satellite Cells, Skeletal Muscle; Signal Transduction
PubMed: 26645687
DOI: 10.1074/jbc.M115.676510 -
Nutrients Oct 2019Diseases involving inflammation and oxidative stress can be exacerbated by high blood glucose levels. Due to tight metabolic regulation, safely reducing blood glucose... (Comparative Study)
Comparative Study
Diseases involving inflammation and oxidative stress can be exacerbated by high blood glucose levels. Due to tight metabolic regulation, safely reducing blood glucose can prove difficult. The ketogenic diet (KD) reduces absolute glucose and insulin, while increasing fatty acid oxidation, ketogenesis, and circulating levels of β-hydroxybutyrate (βHB), acetoacetate (AcAc), and acetone. Compliance to KD can be difficult, so alternative therapies that help reduce glucose levels are needed. Exogenous ketones provide an alternative method to elevate blood ketone levels without strict dietary requirements. In this study, we tested the changes in blood glucose and ketone (βHB) levels in response to acute, sub-chronic, and chronic administration of various ketogenic compounds in either a post-exercise or rested state. WAG/Rij (WR) rats, a rodent model of human absence epilepsy, GLUT1 deficiency syndrome mice (GLUT1D), and wild type Sprague Dawley rats (SPD) were assessed. Non-pathological animals were also assessed across different age ranges. Experimental groups included KD, standard diet (SD) supplemented with water (Control, C) or with exogenous ketones: 1, 3-butanediol (BD), βHB mineral salt (KS), KS with medium chain triglyceride/MCT (KSMCT), BD acetoacetate diester (KE), KE with MCT (KEMCT), and KE with KS (KEKS). In rested WR rats, the KE, KS, KSMCT groups had lower blood glucose level after 1 h of treatment, and in KE and KSMCT groups after 24 h. After exercise, the KE, KSMCT, KEKS, and KEMCT groups had lowered glucose levels after 1 h, and in the KEKS and KEMCT groups after 7 days, compared to control. In GLUT1D mice without exercise, only KE resulted in significantly lower glucose levels at week 2 and week 6 during a 10 weeks long chronic feeding study. In 4-month and 1-year-old SPD rats in the post-exercise trials, blood glucose was significantly lower in KD and KE, and in KEMCT groups, respectively. After seven days, the KSMCT group had the most significantly reduced blood glucose levels, compared to control. These results indicate that exogenous ketones were efficacious in reducing blood glucose levels within and outside the context of exercise in various rodent models of different ages, with and without pathology.
Topics: 3-Hydroxybutyric Acid; Acetoacetates; Animals; Biomarkers; Blood Glucose; Butylene Glycols; Carbohydrate Metabolism, Inborn Errors; Diet, Ketogenic; Dietary Supplements; Disease Models, Animal; Down-Regulation; Epilepsy, Absence; Glucose Transporter Type 1; Male; Mice, Knockout; Monosaccharide Transport Proteins; Physical Exertion; Rats, Sprague-Dawley; Rest; Time Factors
PubMed: 31581549
DOI: 10.3390/nu11102330