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Schiavon FPM, Gazola VAFG, Furlan MMDP, Barrena HC, Bazotte RB. Paradoxical increase in liver ketogenesis during long-term insulin-induced hypoglycemia in diabetic rats. Exp Biol Med (Maywood) 2011; 236:227-32. [DOI: 10.1258/ebm.2010.010266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is well established that insulin inhibits liver ketogenesis. However, during insulin-induced hypoglycemia (IIH) the release of counterregulatory hormones could overcome the insulin effect on ketogenesis. To clarify this question the ketogenic activity in livers from alloxan-diabetic rats submitted to long-term IIH was investigated. Moreover, liver glycogenolysis, gluconeogensis, ureagenesis and the production of l-lactate were measured, and its correlation with blood levels of ketone bodies (KB), l-lactate, glucose, urea and ammonia was investigated. For this purpose, overnight fasted alloxan-diabetic rats (DBT group) were compared with control non-diabetic rats (NDBT group). Long-term IIH was obtained with an intraperitoneal injection of Detemir insulin (1 U/kg), and KB, glucose, l-lactate, ammonia and urea were evaluated at 0, 2, 4, 6, 8 or 10 h after insulin injection. Because IIH was well established two hours after insulin injection this time was used for liver perfusion experiments. The administration of Detemir insulin decreased ( P < 0.05) blood KB and glucose levels, but there was an increase in the blood l-lactate levels and a rebound increase in blood KB during the glucose recovery phase of IIH. In agreement with these results, the capacity to produce KB from octanoate was increased in the livers of DBT rats. Moreover, the elevated blood l-lactate levels in DBT rats could be attributed to the higher ( P < 0.05) glycogenolysis when part of glucose from glycogenolysis enters glycolysis, producing l-lactate. In contrast, except glycerol, gluconeogenesis was negligible in the livers of DBT rats. Therefore, during long-term IIH the higher liver ketogenic capacity of DBT rats increased the risk of hyperketonemia. In addition, in spite of the fact that the insulin injection decreased blood KB, there was a risk of worsening lactic acidosis.
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Affiliation(s)
| | | | | | - Helenton C Barrena
- Department of Pharmacology and Therapeutics, State University of Maringá, Maringá, PR, 87020-900, Brazil
| | - Roberto B Bazotte
- Department of Pharmacology and Therapeutics, State University of Maringá, Maringá, PR, 87020-900, Brazil
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Dasarathy S, Kasumov T, Edmison JM, Gruca LL, Bennett C, Duenas C, Marczewski S, McCullough AJ, Hanson RW, Kalhan SC. Glycine and urea kinetics in nonalcoholic steatohepatitis in human: effect of intralipid infusion. Am J Physiol Gastrointest Liver Physiol 2009; 297:G567-75. [PMID: 19571235 PMCID: PMC2739817 DOI: 10.1152/ajpgi.00042.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The rates of oxidation of glycine and ureagenesis were quantified in the basal state and in response to an intravenous infusion of intralipid with heparin (IL) in healthy subjects (n = 8) and in subjects with nonalcoholic steatohepatitis (NASH) (n = 6). During fasting, no significant difference in weight-specific rate of appearance (R(a)) of glycine, glycine oxidation, and urea synthesis was observed. Intralipid infusion resulted in a significant increase in plasma beta-hydroxybutyrate in both groups. The correlation between free fatty acids and beta-hydroxybutyrate concentration in plasma was 0.94 in NASH compared with 0.4 in controls, indicating greater hepatic fatty acid oxidation in NASH. Intralipid infusion resulted in a significant decrease in urea synthesis and glycine R(a) in both groups and did not impact glycine oxidation. The fractional contribution of glycine carbon to serine was lower in subjects with NASH before and after IL infusion. In contrast, the fractional contribution of serine carbon to cystathionine was higher in NASH before and following IL infusion. These results suggest that hepatic fatty acid oxidation is higher in NASH compared with controls and that glycine oxidation and urea synthesis are not altered. An increase in oxidative stress, induced by a higher rate of fatty acid oxidation in NASH, may have caused an increase in the contribution of serine to cystathionine to meet the higher demands for glutathione.
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Affiliation(s)
- Srinivasan Dasarathy
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Takhar Kasumov
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - John M. Edmison
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Lourdes L. Gruca
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Carole Bennett
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Clarita Duenas
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Susan Marczewski
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Arthur J. McCullough
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Richard W. Hanson
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Satish C. Kalhan
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
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Gazola VAFG, Garcia RF, Curi R, Pithon-Curi TC, Mohamad MS, Hartmann EM, Barrena HC, Bazotte RB. Acute effects of isolated and combinedL-alanine andL-glutamine on hepatic gluconeogenesis, ureagenesis and glycaemic recovery in experimental short-term insulin induced hypoglycaemia. Cell Biochem Funct 2007; 25:211-6. [PMID: 16397910 DOI: 10.1002/cbf.1319] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The acute effects of isolated and combined L-alanine (L-Ala) and L-glutamine (L-Gln) on liver gluconeogenesis, ureagenesis and glycaemic recovery during short-term insulin-induced hypoglycaemia (IIH) were investigated. For this purpose, 24-h fasted rats that received intraperitoneal injection of regular insulin (1.0 U/Kg) were investigated. The control group (COG group) were represented by rats which received saline. The studies were performed 30 min after insulin (IIH group) or saline (COG group) injection. Livers from IIH and COG groups were perfused with basal or saturating levels of L-Ala, L-Gln or L-Gln + L-Ala (L-G + L-A). The production of glucose, urea, L-lactate and pyruvate in livers from IIH and COG group were markedly increased (p < 0.001) when perfused with saturating levels of L-Ala, L-Gln or L-G + L-A compared with basal levels of the same substrates. In addition, livers from IIH rats showed greater ability in producing glucose and urea from saturating levels of L-Ala compared with L-Gln or L-G + L-A. In agreement with these results, the oral administration of L-Ala (100 mg/kg) promoted better glycaemic recovery than L-Gln (100 mg/kg) or the combination of L-G (50 mg/kg) + L-A (50 mg/kg). It can be concluded that L-Ala, but not L-Gln or L-G + L-A could help glycaemic recovery by a mechanism mediated, partly at least, by the increased gluconeogenic and ureagenic efficiency of L-Ala.
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Affiliation(s)
- V A F G Gazola
- Department of Morphophysiological Sciences, State University of Maringá, 87020-900, Maringá, PR, Brazil
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Karbownik M, Reiter RJ, Garcia JJ, Tan DX, Qi W, Manchester LC. Melatonin reduces rat hepatic macromolecular damage due to oxidative stress caused by delta-aminolevulinic acid. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1523:140-6. [PMID: 11042377 DOI: 10.1016/s0304-4165(00)00110-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Delta-aminolevulinic acid, precursor of heme, accumulates in a number of organs, especially in the liver, of patients with acute intermittent porphyria. The potential protective effect of melatonin against oxidative damage to nuclear DNA and microsomal and mitochondrial membranes in rat liver, caused by delta-aminolevulinic acid, was examined. Changes in 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, an index of DNA damage, and alterations in membrane fluidity (the inverse of membrane rigidity) and lipid peroxidation in microsomal and mitochondrial membranes, as indices of damage to lipid and protein molecules in membranes, were estimated. Measurements were made in rat liver after a 2 week treatment with delta-aminolevulinic acid (40 mg/kg b.w., every other day). To test the potential protective effects of melatonin, the indole was injected (i.p. 10 mg/kg b.w.) 3 times daily for 2 weeks. 8-OHdG levels and lipid peroxidation in microsomal membranes increased significantly whereas microsomal and mitochondrial membrane fluidity decreased as a consequence of delta-aminolevulinic acid treatment. Melatonin completely counteracted the effects of delta-aminolevulinic acid. Melatonin was highly effective in protecting against oxidative damage to DNA as well as to microsomal and mitochondrial membranes in rat liver and it may be useful as a cotreatment in patients with acute intermittent porphyria.
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Affiliation(s)
- M Karbownik
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
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Ciprés G, Urcelay E, Butta N, Ayuso MS, Parrilla R, Martín-Requero A. Loss of fatty acid control of gluconeogenesis and PDH complex flux in adrenalectomized rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 267:E528-36. [PMID: 7943301 DOI: 10.1152/ajpendo.1994.267.4.e528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This work aimed to determine the role played by the adrenal gland in the fatty acid control of gluconeogenesis in isolated perfused rat livers. The gluconeogenic substrate concentration responses were not altered in adrenalectomized (ADX) rats. This observation indicates that glucocorticoids are not essential to maintain normal basal gluconeogenic rates. In contrast, fatty acid failed to stimulate gluconeogenesis from lactate and elicited attenuated stimulation with pyruvate as substrate in livers from ADX rats. Fatty acid-induced stimulation of respiration and ketone body production were similar in control and ADX rats. Thus the diminished responsiveness of the gluconeogenic pathway to fatty acid cannot be the result of different rates of energy production and/or generation of reducing power. Fatty acids did not inhibit pyruvate decarboxylation in livers from ADX rats. Even though mitochondria isolated from livers of ADX rats showed normal basal rates of pyruvate metabolism, fatty acids failed to inhibit pyruvate decarboxylation and the activity of the pyruvate dehydrogenase complex. This novel observation of the glucocorticoid effect in controlling the pyruvate dehydrogenase complex responsiveness indicates that the mitochondrial partitioning of pyruvate between carboxylation and decarboxylation reactions may be altered in livers from ADX rats. We propose that the diminished effect of fatty acid in stimulating gluconeogenesis in livers from ADX rats is the result of a limited pyruvate availability for the carboxylase reaction due to a lack of inhibition of flux through the pyruvate dehydrogenase complex.
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Affiliation(s)
- G Ciprés
- Centro de Investigaciones Biológicas, Madrid, Spain
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