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Kajani S, Laker RC, Ratkova E, Will S, Rhodes CJ. Hepatic glucagon action: beyond glucose mobilization. Physiol Rev 2024; 104:1021-1060. [PMID: 38300523 DOI: 10.1152/physrev.00028.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 02/02/2024] Open
Abstract
Glucagon's ability to promote hepatic glucose production has been known for over a century, with initial observations touting this hormone as a diabetogenic agent. However, glucagon receptor agonism [when balanced with an incretin, including glucagon-like peptide 1 (GLP-1) to dampen glucose excursions] is now being developed as a promising therapeutic target in the treatment of metabolic diseases, like metabolic dysfunction-associated steatotic disease/metabolic dysfunction-associated steatohepatitis (MASLD/MASH), and may also have benefit for obesity and chronic kidney disease. Conventionally regarded as the opposing tag-team partner of the anabolic mediator insulin, glucagon is gradually emerging as more than just a "catabolic hormone." Glucagon action on glucose homeostasis within the liver has been well characterized. However, growing evidence, in part thanks to new and sensitive "omics" technologies, has implicated glucagon as more than just a "glucose liberator." Elucidation of glucagon's capacity to increase fatty acid oxidation while attenuating endogenous lipid synthesis speaks to the dichotomous nature of the hormone. Furthermore, glucagon action is not limited to just glucose homeostasis and lipid metabolism, as traditionally reported. Glucagon plays key regulatory roles in hepatic amino acid and ketone body metabolism, as well as mitochondrial turnover and function, indicating broader glucagon signaling consequences for metabolic homeostasis mediated by the liver. Here we examine the broadening role of glucagon signaling within the hepatocyte and question the current dogma, to appreciate glucagon as more than just that "catabolic hormone."
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Affiliation(s)
- Sarina Kajani
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Rhianna C Laker
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Ekaterina Ratkova
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Mölndal, Sweden
| | - Sarah Will
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Christopher J Rhodes
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
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Venable AH, Lee LE, Feola K, Santoyo J, Broomfield T, Huen SC. Fasting-induced renal HMGCS2 expression does not contribute to circulating ketones. Am J Physiol Renal Physiol 2022; 322:F460-F467. [PMID: 35224990 PMCID: PMC9076412 DOI: 10.1152/ajprenal.00447.2021] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial hydroxymethylglutaryl-CoA synthase 2 (HMGCS2) is the rate-limiting enzyme in ketogenesis. The liver expresses high levels of HMGCS2 constitutively as the main ketogenic organ. It has been suggested that the kidney could be ketogenic as HMGCS2 is expressed in the kidney during fasting and diabetic conditions. However, definitive proof of the capacity for the kidney to produce ketones is lacking. We demonstrate that during fasting, HMGCS2 expression is induced in the proximal tubule of the kidney and is peroxisome proliferator-activated receptor-alpha dependent. Mice with kidney-specific Hmgcs2 deletion show a minor, likely physiologically insignificant, decrease in circulating ketones during fasting. Conversely, liver-specific Hmgcs2 knockout mice exhibit a complete loss of fasting ketosis. Together, these findings indicate renal HMGCS2 does not significantly contribute to global ketone production, and during fasting, the increase in circulating ketones is solely dependent on hepatic HMGCS2. Proximal tubule HMGCS2 serves functions other than systemic ketone provision.
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Affiliation(s)
- Andrea H Venable
- Department of Internal Medicine (Nephrology) and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Lauren Elizabeth Lee
- Department of Internal Medicine (Nephrology) and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kyle Feola
- Department of Internal Medicine (Nephrology) and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - John Santoyo
- Department of Internal Medicine (Nephrology) and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Tatyana Broomfield
- Department of Internal Medicine (Nephrology) and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sarah C Huen
- Department of Internal Medicine (Nephrology) and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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Liver disease in obesity and underweight: the two sides of the coin. A narrative review. Eat Weight Disord 2021; 26:2097-2107. [PMID: 33150534 DOI: 10.1007/s40519-020-01060-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 10/16/2020] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Malnutrition, whether characterized by not enough or too much nutrient intake, is detrimental to the liver. We herein provide a narrative literature revision relative to hepatic disease occurrence in over or undernourished subjects, to shed light on the paradox where both sides of malnutrition lead to similar liver dysfunction and fat accumulation. METHODS Medline, EMBASE, and Cochrane Library were searched for publications up to July 2020. Articles discussing the association between both chronic and acute liver pathology and malnutrition were evaluated together with studies reporting the dietary intake in subjects affected by malnutrition. RESULTS The association between overnutrition and non-alcoholic fatty liver disease (NAFLD) is well recognized, as the beneficial effects of calorie restriction and very low carbohydrate diets. Conversely, the link between undernutrition and liver injury is more complex and less understood. In developing countries, early exposure to nutrient deficiency leads to marasmus and kwashiorkor, accompanied by fatty liver, whereas in developed countries anorexia nervosa is a more common form of undernutrition, associated with liver injury. Weight gain in undernutrition is associated with liver function improvement, whereas no study on the impact of macronutrient distribution is available. We hypothesized a role for very low carbohydrate diets in the management of undernutrition derived liver pathology, in addition to the established one in overnutrition-related NAFLD. CONCLUSIONS Further studies are warranted to update the knowledge regarding undernutrition-related liver disease, and a specific interest should be paid to macronutrient distribution both in the context of refeeding and relative to its role in the development of hepatic complications of anorexia nervosa. LEVEL OF EVIDENCE Narrative review, Level V.
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Lactation Ketoacidosis: A Systematic Review of Case Reports. ACTA ACUST UNITED AC 2020; 56:medicina56060299. [PMID: 32560535 PMCID: PMC7353886 DOI: 10.3390/medicina56060299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 12/29/2022]
Abstract
Background and Objective: Lactation ketoacidosis is a rare cause of high anion gap metabolic acidosis affecting breastfeeding mothers. We aim to review and analyze all cases of lactation ketoacidosis reported. Materials and Methods: A systematic search of PubMed/MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINAHL), identifying relevant case reports published from 1 January 1970 to 31 December 2019. We extracted the following data: the first author, country, year of publication, age of the mother, age of the child, weight/body mass index (BMI) of the mother, precipitating factors, presenting symptoms, biochemical results, treatment, breastfeeding, and time from presentation to the resolution of ketoacidosis. Results: Sixteen case reports and 1 case series reporting 18 cases of lactation ketoacidosis were found. Presenting symptoms were nausea (72%, 13/18), vomiting (67%, 12/18), malaise (56%, 10/18), abdominal pain (44%, 8/18), dyspnea (33%, 6/18), headache (22%, 4/18), and palpitation (11%, 2/18). Dieting and physical exercise to lose weight were reported in 76% (14/18). The treatments included IV dextrose, sodium bicarbonate, insulin, rehydration, monitoring and replacement of electrolytes, and resumption of a balanced diet. The prognoses were good, with no mortalities. Conclusions: lactation ketoacidosis should be suspected in unwell breastfeeding women with high anion gap metabolic acidosis, after excluding other causes.
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Kleinert M, Sachs S, Habegger KM, Hofmann SM, Müller TD. Glucagon Regulation of Energy Expenditure. Int J Mol Sci 2019; 20:ijms20215407. [PMID: 31671603 PMCID: PMC6862306 DOI: 10.3390/ijms20215407] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023] Open
Abstract
Glucagon's ability to increase energy expenditure has been known for more than 60 years, yet the mechanisms underlining glucagon's thermogenic effect still remain largely elusive. Over the last years, significant efforts were directed to unravel the physiological and cellular underpinnings of how glucagon regulates energy expenditure. In this review, we summarize the current knowledge on how glucagon regulates systems metabolism with a special emphasis on its acute and chronic thermogenic effects.
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Affiliation(s)
- Maximilian Kleinert
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Stephan Sachs
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
- Division of Metabolic Diseases, Technische Universität München, 85740 Munich, Germany.
| | - Kirk M Habegger
- Department of Medicine-Endocrinology and Comprehensive Diabetes Center, Diabetes and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35899, USA.
| | - Susanna M Hofmann
- Institute for Diabetes and Regeneration, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
- Medizinische Klinik und Poliklinik IV, Klinikum der LMU, 80336 München, Germany.
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, 72076 Tübingen, Germany.
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Danne T, Garg S, Peters AL, Buse JB, Mathieu C, Pettus JH, Alexander CM, Battelino T, Ampudia-Blasco FJ, Bode BW, Cariou B, Close KL, Dandona P, Dutta S, Ferrannini E, Fourlanos S, Grunberger G, Heller SR, Henry RR, Kurian MJ, Kushner JA, Oron T, Parkin CG, Pieber TR, Rodbard HW, Schatz D, Skyler JS, Tamborlane WV, Yokote K, Phillip M. International Consensus on Risk Management of Diabetic Ketoacidosis in Patients With Type 1 Diabetes Treated With Sodium-Glucose Cotransporter (SGLT) Inhibitors. Diabetes Care 2019; 42:1147-1154. [PMID: 30728224 PMCID: PMC6973545 DOI: 10.2337/dc18-2316] [Citation(s) in RCA: 213] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sodium-glucose cotransporter (SGLT) inhibitors are new oral antidiabetes medications shown to effectively reduce glycated hemoglobin (A1C) and glycemic variability, blood pressure, and body weight without intrinsic properties to cause hypoglycemia in people with type 1 diabetes. However, recent studies, particularly in individuals with type 1 diabetes, have demonstrated increases in the absolute risk of diabetic ketoacidosis (DKA). Some cases presented with near-normal blood glucose levels or mild hyperglycemia, complicating the recognition/diagnosis of DKA and potentially delaying treatment. Several SGLT inhibitors are currently under review by the U.S. Food and Drug Administration and European regulatory agencies as adjuncts to insulin therapy in people with type 1 diabetes. Strategies must be developed and disseminated to the medical community to mitigate the associated DKA risk. This Consensus Report reviews current data regarding SGLT inhibitor use and provides recommendations to enhance the safety of SGLT inhibitors in people with type 1 diabetes.
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Affiliation(s)
- Thomas Danne
- Diabetes Centre for Children and Adolescents, Kinder- und Jugendkrankenhaus Auf der Bult, Hannover, Germany
| | - Satish Garg
- University of Colorado Denver and Barbara Davis Center for Diabetes, Aurora, CO
| | - Anne L Peters
- Keck School of Medicine of the University of Southern California, Los Angeles, CA
| | - John B Buse
- University of North Carolina School of Medicine, Chapel Hill, NC
| | - Chantal Mathieu
- Department of Endocrinology, UZ Gasthuisberg, KU Leuven, Leuven, Belgium
| | - Jeremy H Pettus
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, San Diego, CA
| | | | - Tadej Battelino
- Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children's Hospital, University Medical Centre Ljubljana, and Faculty of Medicine, University of Ljubljana, Slovenia
| | | | | | - Bertrand Cariou
- Clinique d'endocrinologie, L'institut du thorax, CHU Nantes, CIC 1413 INSERM, Nantes, France
| | | | - Paresh Dandona
- Division of Endocrinology, Diabetes and Metabolism, University at Buffalo, The State University of New York, Buffalo, NY
| | | | - Ele Ferrannini
- National Research Council (CNR) Institute of Clinical Physiology, Pisa, Italy
| | - Spiros Fourlanos
- Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Melbourne, Australia
| | | | - Simon R Heller
- Academic Unit of Diabetes, Endocrinology & Metabolism, University of Sheffield, Sheffield, U.K
| | - Robert R Henry
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, San Diego, CA
| | | | | | - Tal Oron
- Jesse Z and Sara Lea Shafer Institute of Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Thomas R Pieber
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | | | - Desmond Schatz
- Division of Endocrinology, Department of Pediatrics, University of Florida, Gainesville, FL
| | - Jay S Skyler
- Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL
| | | | - Koutaro Yokote
- Department of Diabetes, Metabolism and Endocrinology, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Moshe Phillip
- Jesse Z and Sara Lea Shafer Institute of Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Khare P, Mangal P, Baboota RK, Jagtap S, Kumar V, Singh DP, Boparai RK, Sharma SS, Khardori R, Bhadada SK, Kondepudi KK, Chopra K, Bishnoi M. Involvement of Glucagon in Preventive Effect of Menthol Against High Fat Diet Induced Obesity in Mice. Front Pharmacol 2018; 9:1244. [PMID: 30505271 PMCID: PMC6250823 DOI: 10.3389/fphar.2018.01244] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/12/2018] [Indexed: 11/13/2022] Open
Abstract
Glucagon mediated mechanisms have been shown to play clinically significant role in energy expenditure. The present study was designed to understand whether pharmacological mimicking of cold using menthol (TRPM8 modulator) can induce glucagon-mediated energy expenditure to prevent weight gain and related complications. Acute oral and topical administration of TRPM8 agonists (menthol and icilin) increased serum glucagon concentration which was prevented by pre-treatment with AMTB, a TRPM8 blocker. Chronic administration of menthol (50 and 100 mg/kg/day for 12 weeks) to HFD fed animals prevented weight gain, insulin resistance, adipose tissue hypertrophy and triacylglycerol deposition in liver. These effects were not restricted to oral administration, but also observed upon the topical application of menthol (10% w/v). The metabolic alterations caused by menthol in liver and adipose tissue mirrored the known effects of glucagon, such as increased glycogenolysis and gluconeogenesis in the liver, and enhanced thermogenic activity of white and brown adipose tissue. Correlation analysis suggests a strong correlation between glucagon dependent changes and energy expenditure markers. Interestingly, in-vitro treatment of the serum of menthol treated mice increased energy expenditure markers in mature 3T3L1 adipocytes, which was prevented in the presence of non-competitive glucagon receptor antagonist, L-168,049, indicating that menthol-induced increase in serum glucagon is responsible for increase in energy expenditure phenotype. In conclusion, the present work provides evidence that glucagon plays an important role in the preventive effect of menthol against HFD-induced weight gain and related complications.
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Affiliation(s)
- Pragyanshu Khare
- National Agri-Food Biotechnology Institute, Sahibzada Ajit Singh Nagar, India.,Department of Pharmacology, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Priyanka Mangal
- Department of Natural Products, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, India
| | - Ritesh K Baboota
- National Agri-Food Biotechnology Institute, Sahibzada Ajit Singh Nagar, India
| | - Sneha Jagtap
- Department of Natural Products, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, India
| | - Vijay Kumar
- National Agri-Food Biotechnology Institute, Sahibzada Ajit Singh Nagar, India
| | | | - Ravneet K Boparai
- Department of Biotechnology, Government College for Girls, Chandigarh, India
| | - Shyam S Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sahibzada Ajit Singh Nagar, India
| | - Romesh Khardori
- Division of Endocrinology and Metabolism, The EVMS Sterling Centre of Diabetes and Endocrine Disorders, Department of Internal Medicine, East Virginia Medical School, Norfolk, VA, United States
| | - Sanjay K Bhadada
- Department of Endocrinology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Kanthi K Kondepudi
- National Agri-Food Biotechnology Institute, Sahibzada Ajit Singh Nagar, India
| | - Kanwaljit Chopra
- Department of Pharmacology, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India
| | - Mahendra Bishnoi
- National Agri-Food Biotechnology Institute, Sahibzada Ajit Singh Nagar, India
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Swisa A, Avrahami D, Eden N, Zhang J, Feleke E, Dahan T, Cohen-Tayar Y, Stolovich-Rain M, Kaestner KH, Glaser B, Ashery-Padan R, Dor Y. PAX6 maintains β cell identity by repressing genes of alternative islet cell types. J Clin Invest 2016; 127:230-243. [PMID: 27941241 DOI: 10.1172/jci88015] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022] Open
Abstract
Type 2 diabetes is thought to involve a compromised β cell differentiation state, but the mechanisms underlying this dysfunction remain unclear. Here, we report a key role for the TF PAX6 in the maintenance of adult β cell identity and function. PAX6 was downregulated in β cells of diabetic db/db mice and in WT mice treated with an insulin receptor antagonist, revealing metabolic control of expression. Deletion of Pax6 in β cells of adult mice led to lethal hyperglycemia and ketosis that were attributed to loss of β cell function and expansion of α cells. Lineage-tracing, transcriptome, and chromatin analyses showed that PAX6 is a direct activator of β cell genes, thus maintaining mature β cell function and identity. In parallel, we found that PAX6 binds promoters and enhancers to repress alternative islet cell genes including ghrelin, glucagon, and somatostatin. Chromatin analysis and shRNA-mediated gene suppression experiments indicated a similar function of PAX6 in human β cells. We conclude that reduced expression of PAX6 in metabolically stressed β cells may contribute to β cell failure and α cell dysfunction in diabetes.
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McCarty MF, DiNicolantonio JJ. Lauric acid-rich medium-chain triglycerides can substitute for other oils in cooking applications and may have limited pathogenicity. Open Heart 2016; 3:e000467. [PMID: 27547436 PMCID: PMC4975867 DOI: 10.1136/openhrt-2016-000467] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/09/2016] [Accepted: 07/02/2016] [Indexed: 12/21/2022] Open
Abstract
Recently, medium-chain triglycerides (MCTs) containing a large fraction of lauric acid (LA) (C12)-about 30%-have been introduced commercially for use in salad oils and in cooking applications. As compared to the long-chain fatty acids found in other cooking oils, the medium-chain fats in MCTs are far less likely to be stored in adipose tissue, do not give rise to 'ectopic fat' metabolites that promote insulin resistance and inflammation, and may be less likely to activate macrophages. When ingested, medium-chain fatty acids are rapidly oxidised in hepatic mitochondria; the resulting glut of acetyl-coenzyme A drives ketone body production and also provokes a thermogenic response. Hence, studies in animals and humans indicate that MCT ingestion is less obesogenic than comparable intakes of longer chain oils. Although LA tends to raise serum cholesterol, it has a more substantial impact on high density lipoprotein (HDL) than low density lipoprotein (LDL) in this regard, such that the ratio of total cholesterol to HDL cholesterol decreases. LA constitutes about 50% of the fatty acid content of coconut oil; south Asian and Oceanic societies which use coconut oil as their primary source of dietary fat tend to be at low cardiovascular risk. Since ketone bodies can exert neuroprotective effects, the moderate ketosis induced by regular MCT ingestion may have neuroprotective potential. As compared to traditional MCTs featuring C6-C10, laurate-rich MCTs are more feasible for use in moderate-temperature frying and tend to produce a lower but more sustained pattern of blood ketone elevation owing to the more gradual hepatic oxidation of ingested laurate.
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Kanikarla-Marie P, Jain SK. Hyperketonemia and ketosis increase the risk of complications in type 1 diabetes. Free Radic Biol Med 2016; 95:268-77. [PMID: 27036365 PMCID: PMC4867238 DOI: 10.1016/j.freeradbiomed.2016.03.020] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 03/16/2016] [Accepted: 03/21/2016] [Indexed: 12/19/2022]
Abstract
Diets that boost ketone production are increasingly used for treating several neurological disorders. Elevation in ketones in most cases is considered favorable, as they provide energy and are efficient in fueling the body's energy needs. Despite all the benefits from ketones, the above normal elevation in the concentration of ketones in the circulation tend to illicit various pathological complications by activating injurious pathways leading to cellular damage. Recent literature demonstrates a plausible link between elevated levels of circulating ketones and oxidative stress, linking hyperketonemia to innumerable morbid conditions. Ketone bodies are produced by the oxidation of fatty acids in the liver as a source of alternative energy that generally occurs in glucose limiting conditions. Regulation of ketogenesis and ketolysis plays an important role in dictating ketone concentrations in the blood. Hyperketonemia is a condition with elevated blood levels of acetoacetate, 3-β-hydroxybutyrate, and acetone. Several physiological and pathological triggers, such as fasting, ketogenic diet, and diabetes cause an accumulation and elevation of circulating ketones. Complications of the brain, kidney, liver, and microvasculature were found to be elevated in diabetic patients who had elevated ketones compared to those diabetics with normal ketone levels. This review summarizes the mechanisms by which hyperketonemia and ketoacidosis cause an increase in redox imbalance and thereby increase the risk of morbidity and mortality in patients.
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Affiliation(s)
- Preeti Kanikarla-Marie
- Department of Pediatrics, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
| | - Sushil K Jain
- Department of Pediatrics, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA.
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Adams JH, Irving G, Koeslag JH, Lochner JD, Sandell RC, Wilkinson C. Beta-adrenergic blockade restores glucose's antiketogenic activity after exercise in carbohydrate-depleted athletes. J Physiol 1987; 386:439-54. [PMID: 3316599 PMCID: PMC1192471 DOI: 10.1113/jphysiol.1987.sp016543] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
1. The development of post-exercise ketosis is not abolished by the ingestion of glucose immediately after exercise, despite inducing high insulin/glucagon ratios in the peripheral (and therefore by implication in the portal) blood. 2. To investigate the possibility of autonomic control of the liver influencing its sensitivity to the major counter-regulatory hormones, we administered 50 g glucose, either on its own, or together with 0.5 mg prazosine, 40 mg propranolol, or 15 mg propantheline, to forty-seven 48 h carbohydrate-starved athletes who had just run 25 km. 3. The blood 3-hydroxybutyrate concentration rose from 0.30 +/- 0.05 (mean +/- S.E. of mean) to 0.52 +/- 0.08 mmol/l with exercise, and then to 1.32 +/- 0.40 mmol/l at 6 h after exercise in subjects who had ingested only glucose after exercise. 4. The effects of prazosine and propantheline on the blood ketone body concentration at 2 h after exercise was not statistically significant. Propranolol, on the other hand, significantly lowered the blood 3-hydroxybutyrate concentration (compared with controls) to 0.09 +/- 0.03 mmol/l at 3 h (P less than 0.01), and 0.35 +/- 0.08 mmol/l at 6 h (P less than 0.01) after exercise. 5. The plasma insulin, glucagon, glucose and free fatty acid concentrations were unaffected by propranolol, indicating that the antiketogenesis was the result of a direct effect on ketone body metabolism. 6. Since beta-adrenergic blockade has not previously been shown to have antiketogenic activity, except in somatostatin-induced hyperketonaemia, it is concluded that its effectiveness in post-exercise ketosis can probably be ascribed to a functional hepatic insulin and glucagon deficiency.
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Affiliation(s)
- J H Adams
- Metropolitan Sport Science Centre, University of Cape Town Medical School, South Africa
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12
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Koeslag JH, Levinrad LI, Lochner JD, Sive AA. Post-exercise ketosis in post-prandial exercise: effect of glucose and alanine ingestion in humans. J Physiol 1985; 358:395-403. [PMID: 3884775 PMCID: PMC1193348 DOI: 10.1113/jphysiol.1985.sp015557] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
This study examined ketosis in response to 90 min of running before and after the ingestion of 50 g glucose or 50 g L-alanine in thirty-three athletes. Everyone ran 20 km at 07.30 h and then rested, while fasting, till 16.00 h. There were four test groups: 'glucose-before', 'glucose-after', 'alanine-before' and 'alanine-after' according to whether glucose or alanine was ingested at 07.00 h, or 09.00 h. Controls did not ingest either test substance. The control 3-hydroxybutyrate concentration rose from 0.23 +/- 0.03 mmol/l (S.E. of mean) at 07.00 h to 0.74 +/- 0.27 mmol/l at 12.00 h, and 0.94 +/- 0.33 mmol/l at 16.00 h. Glucose ingestion before or after exercise did not influence post-exercise ketosis significantly, despite high insulin: glucagon ratios, low free fatty acid concentrations and hyperglycaemia. Alanine significantly lowered the 3-hydroxybutyrate levels, especially after exercise (to 0.14 +/- 0.07 mmol/l at 12.00 h; P less than 0.05) despite reversed insulin: glucagon ratios. This suggests that hepatic responsiveness to portal hyperglycaemia and the main hormones of metabolism is altered immediately after exercise, presumably to promote muscle glycogen synthesis in preference to liver glycogen synthesis.
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Cook GA, Otto DA, Cornell NW. Malonyl-CoA inhibition of carnitine palmitoyltransferase: interpretation of I50 and K1 values. Biochem J 1983; 212:525-7. [PMID: 6882381 PMCID: PMC1152077 DOI: 10.1042/bj2120525] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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