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Faivre A, Verissimo T, Auwerx H, Legouis D, de Seigneux S. Tubular Cell Glucose Metabolism Shift During Acute and Chronic Injuries. Front Med (Lausanne) 2021; 8:742072. [PMID: 34778303 PMCID: PMC8585753 DOI: 10.3389/fmed.2021.742072] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/11/2021] [Indexed: 12/28/2022] Open
Abstract
Acute and chronic kidney disease are responsible for large healthcare costs worldwide. During injury, kidney metabolism undergoes profound modifications in order to adapt to oxygen and nutrient shortage. Several studies highlighted recently the importance of these metabolic adaptations in acute as well as in chronic phases of renal disease, with a potential deleterious effect on fibrosis progression. Until recently, glucose metabolism in the kidney has been poorly studied, even though the kidney has the capacity to use and produce glucose, depending on the segment of the nephron. During physiology, renal proximal tubular cells use the beta-oxidation of fatty acid to generate large amounts of energy, and can also produce glucose through gluconeogenesis. In acute kidney injury, proximal tubular cells metabolism undergo a metabolic shift, shifting away from beta-oxidation of fatty acids and gluconeogenesis toward glycolysis. In chronic kidney disease, the loss of fatty acid oxidation is also well-described, and data about glucose metabolism are emerging. We here review the modifications of proximal tubular cells glucose metabolism during acute and chronic kidney disease and their potential consequences, as well as the potential therapeutic implications.
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Affiliation(s)
- Anna Faivre
- Laboratory of Nephrology, Geneva University Hospitals, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Thomas Verissimo
- Laboratory of Nephrology, Geneva University Hospitals, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Hannah Auwerx
- Laboratory of Nephrology, Geneva University Hospitals, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - David Legouis
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.,Intensive Care Unit, Department of Acute Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Sophie de Seigneux
- Laboratory of Nephrology, Geneva University Hospitals, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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Legouis D, Faivre A, Cippà PE, de Seigneux S. Renal gluconeogenesis: an underestimated role of the kidney in systemic glucose metabolism. Nephrol Dial Transplant 2020; 37:1417-1425. [PMID: 33247734 DOI: 10.1093/ndt/gfaa302] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Indexed: 12/21/2022] Open
Abstract
Glucose levels are tightly regulated at all times. Gluconeogenesis is the metabolic pathway dedicated to glucose synthesis from non-hexose precursors. Gluconeogenesis is critical for glucose homoeostasis, particularly during fasting or stress conditions. The renal contribution to systemic gluconeogenesis is increasingly recognized. During the post-absorptive phase, the kidney accounts for ∼40% of endogenous gluconeogenesis, occurring mainly in the kidney proximal tubule. The main substrate for renal gluconeogenesis is lactate and the process is regulated by insulin and cellular glucose levels, but also by acidosis and stress hormones. The kidney thus plays an important role in the maintenance of glucose and lactate homoeostasis during stress conditions. The impact of acute and chronic kidney disease and proximal tubular injury on gluconeogenesis is not well studied. Recent evidence shows that in both experimental and clinical acute kidney injury, impaired renal gluconeogenesis could significantly participate in systemic metabolic disturbance and thus alter the prognosis. This review summarizes the biochemistry of gluconeogenesis, the current knowledge of kidney gluconeogenesis, its modifications in kidney disease and the clinical relevance of this fundamental biological process in human biology.
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Affiliation(s)
- David Legouis
- Department of Acute Medicine, Division of Intensive Care, University Hospitals of Geneva, Geneva, Switzerland.,Department of Medicine, Laboratory of Nephrology, University Hospitals of Geneva, Geneva, Switzerland.,Department of Cell Physiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anna Faivre
- Department of Medicine, Laboratory of Nephrology, University Hospitals of Geneva, Geneva, Switzerland.,Department of Cell Physiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pietro E Cippà
- Division of Nephrology, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Sophie de Seigneux
- Department of Medicine, Laboratory of Nephrology, University Hospitals of Geneva, Geneva, Switzerland.,Department of Cell Physiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Medicine, Division of Nephrology, University Hospitals of Geneva, Geneva, Switzerland
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3
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Sasaki M, Sasako T, Kubota N, Sakurai Y, Takamoto I, Kubota T, Inagi R, Seki G, Goto M, Ueki K, Nangaku M, Jomori T, Kadowaki T. Dual Regulation of Gluconeogenesis by Insulin and Glucose in the Proximal Tubules of the Kidney. Diabetes 2017. [PMID: 28630133 DOI: 10.2337/db16-1602] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Growing attention has been focused on the roles of the proximal tubules (PTs) of the kidney in glucose metabolism, including the mechanism of regulation of gluconeogenesis. In this study, we found that PT-specific insulin receptor substrate 1/2 double-knockout mice, established by using the newly generated sodium-glucose cotransporter 2 (SGLT2)-Cre transgenic mice, exhibited impaired insulin signaling and upregulated gluconeogenic gene expression and renal gluconeogenesis, resulting in systemic insulin resistance. In contrast, in streptozotocin-treated mice, although insulin action was impaired in the PTs, the gluconeogenic gene expression was unexpectedly downregulated in the renal cortex, which was restored by administration of an SGLT1/2 inhibitor. In the HK-2 cells, the gluconeogenic gene expression was suppressed by insulin, accompanied by phosphorylation and inactivation of forkhead box transcription factor 1 (FoxO1). In contrast, glucose deacetylated peroxisome proliferator-activated receptor γ coactivator 1-α (PGC1α), a coactivator of FoxO1, via sirtuin 1, suppressing the gluconeogenic gene expression, which was reversed by inhibition of glucose reabsorption. These data suggest that both insulin signaling and glucose reabsorption suppress the gluconeogenic gene expression by inactivation of FoxO1 and PGC1α, respectively, providing insight into novel mechanisms underlying the regulation of gluconeogenesis in the PTs.
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Affiliation(s)
- Motohiro Sasaki
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Mie Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., Mie, Japan
| | - Takayoshi Sasako
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Translational Systems Biology and Medicine Initiative, The University of Tokyo, Tokyo, Japan
- Department of Molecular Diabetic Medicine, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan
| | - Naoto Kubota
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Translational Systems Biology and Medicine Initiative, The University of Tokyo, Tokyo, Japan
- Department of Clinical Nutrition Therapy, The University of Tokyo Hospital, The University of Tokyo, Tokyo, Japan
- Clinical Nutrition Program, National Institute of Health and Nutrition, Tokyo, Japan
- Laboratory for Metabolic Homeostasis, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan
| | - Yoshitaka Sakurai
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Iseki Takamoto
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tetsuya Kubota
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Clinical Nutrition Program, National Institute of Health and Nutrition, Tokyo, Japan
- Laboratory for Metabolic Homeostasis, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan
| | - Reiko Inagi
- Department of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | | | - Moritaka Goto
- Mie Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., Mie, Japan
| | - Kohjiro Ueki
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Translational Systems Biology and Medicine Initiative, The University of Tokyo, Tokyo, Japan
- Department of Molecular Diabetic Medicine, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan
| | - Masaomi Nangaku
- Department of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Takahito Jomori
- Mie Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., Mie, Japan
| | - Takashi Kadowaki
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Translational Systems Biology and Medicine Initiative, The University of Tokyo, Tokyo, Japan
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4
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Scholljegerdes EJ, Summers AF. How do we identify energetically efficient grazing animals?1. J Anim Sci 2016. [DOI: 10.2527/jas.2016-0653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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5
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Zhang Q, Koser SL, Donkin SS. Propionate induces mRNA expression of gluconeogenic genes in bovine calf hepatocytes. J Dairy Sci 2016; 99:3908-3915. [DOI: 10.3168/jds.2015-10312] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/04/2015] [Indexed: 11/19/2022]
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6
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Effects of a single glucocorticoid injection on propylene glycol-treated cows with clinical ketosis. Vet J 2015; 204:144-9. [DOI: 10.1016/j.tvjl.2015.01.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/14/2015] [Accepted: 01/19/2015] [Indexed: 11/23/2022]
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7
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Noro M, Bertinat R, Yañez A, Slebe J, Wittwer F. Non-protein nitrogen supplementation increases gluconeogenic capacity in sheep. Livest Sci 2012. [DOI: 10.1016/j.livsci.2012.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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8
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Aschenbach JR, Kristensen NB, Donkin SS, Hammon HM, Penner GB. Gluconeogenesis in dairy cows: the secret of making sweet milk from sour dough. IUBMB Life 2011; 62:869-77. [PMID: 21171012 DOI: 10.1002/iub.400] [Citation(s) in RCA: 301] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Gluconeogenesis is a crucial process to support glucose homeostasis when nutritional supply with glucose is insufficient. Because ingested carbohydrates are efficiently fermented to short-chain fatty acids in the rumen, ruminants are required to meet the largest part of their glucose demand by de novo genesis after weaning. The qualitative difference to nonruminant species is that propionate originating from ruminal metabolism is the major substrate for gluconeogenesis. Disposal of propionate into gluconeogenesis via propionyl-CoA carboxylase, methylmalonyl-CoA mutase, and the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK) has a high metabolic priority and continues even if glucose is exogenously supplied. Gluconeogenesis is regulated at the transcriptional and several posttranscriptional levels and is under hormonal control (primarily insulin, glucagon, and growth hormone). Transcriptional regulation is relevant for regulating precursor entry into gluconeogenesis (propionate, alanine and other amino acids, lactate, and glycerol). Promoters of the bovine pyruvate carboxylase (PC) and PEPCK genes are directly controlled by metabolic products. The final steps decisive for glucose release (fructose 1,6-bisphosphatase and glucose 6-phosphatase) appear to be highly dependent on posttranscriptional regulation according to actual glucose status. Glucogenic precursor entry, together with hepatic glycogen dynamics, is mostly sufficient to meet the needs for hepatic glucose output except in high-producing dairy cows during the transition from the dry period to peak lactation. Lactating cows adapt to the increased glucose requirement for lactose production by mobilization of endogenous glucogenic substrates and increased hepatic PC expression. If these adaptations fail, lipid metabolism may be altered leading to fatty liver and ketosis. Increasing feed intake and provision of glucogenic precursors from the diet are important to ameliorate these disturbances. An improved understanding of the complex mechanisms underlying gluconeogenesis may further improve our options to enhance the postpartum health status of dairy cows.
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Affiliation(s)
- Jörg R Aschenbach
- Department of Veterinary Medicine, Institute of Veterinary Physiology, Free University of Berlin, Berlin, Germany.
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9
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Velez JC, Donkin SS. Feed restriction induces pyruvate carboxylase but not phosphoenolpyruvate carboxykinase in dairy cows. J Dairy Sci 2006; 88:2938-48. [PMID: 16027208 DOI: 10.3168/jds.s0022-0302(05)72974-x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The ability of dairy cattle to adapt to changes in nutrient intake requires appropriately responsive expression of several key genes in liver. Holstein cows were used in 2 experiments to determine the effect of short-term feed restriction on expression of mRNA for gluconeogenic and ureagenic enzymes in liver. In experiment 1, cows were fed a total mixed diet for ad libitum intake for a 5-d period followed by 5 d of 50% of their previous 5-d ad libitum intake followed by 10 d of ad libitum feeding. Liver biopsies and blood samples were obtained on d 5, 10, and 20 of the experiment, the last day of each feeding period. Pyruvate carboxylase (PC) mRNA increased with feed restriction, but phosphoenolpyruvate carboxykinase (PEPCK) was unchanged. Expression of carbamoyl phosphate synthetase (CPS-I), argininosuccinate synthetase, and ornithine transcarbamylase mRNA were not altered by feed restriction; however, CPS-I mRNA expression tended to increase during realimentation. In experiment 2, cows were fed for ad libitum intake for 5 d and then fed 50% of previous intake for 5 d. Liver biopsy samples collected on d 5 and 10 were used for PC mRNA, PEPCK mRNA, and in vitro measure of gluconeogenesis from radiolabelled propionate and lactate. The data indicate expression of genes for key metabolic processes in liver of lactating cows is responsive to feeding level. Expression of PC mRNA is part of the adaptive response to feed intake restriction and is matched by increased capacity for gluconeogenesis from lactate.
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Affiliation(s)
- J C Velez
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA
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10
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Hammon HM, Philipona C, Zbinden Y, Blum JW, Donkin SS. Effects of Dexamethasone and Growth Hormone Treatment on Hepatic Gluconeogenic Enzymes in Calves. J Dairy Sci 2005; 88:2107-16. [PMID: 15905441 DOI: 10.3168/jds.s0022-0302(05)72887-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothesis was tested that dexamethasone (DX) and bovine somatotropin (bST) alter expression or activity of gluconeogenic enzymes in neonatal calves. Holstein dairy calves (n = 24) were randomly divided in 4 groups and were treated with saline (control group), with DX at 30 microg/kg body weight per d (CDX), with 500 mg of sustained-release recombinant bST every 14 d (CbST), and with the combination of DX and bST from d 3 through 42 of life (CbSTDX). Plasma glucose and insulin concentrations were elevated throughout the study in CbSTDX, and insulin concentrations were elevated in CDX from d 7 to 28. Treatment with DX and the combination of DX and bST increased plasma glucagon concentrations from d 14 to 42, but decreased plasma cortisol concentrations on d 7 and 14 when compared with control calves. In liver, phosphoenolpyruvate carboxykinase (PEPCK) mRNA levels were reduced in CDX and CbSTDX when compared with control calves or CbST. The activity of PEPCK on d 14 was higher in CbSTDX compared with control calves. Pyruvate carboxylase mRNA levels were decreased on d 7 in CDX and CbSTDX. Pyruvate carboxylase activities on d 14 and 28 were lower in CDX and CbSTDX than in control calves or CbST. These data indicate an age-dependent response to DX for blood metabolites, expression and activities of hepatic PEPCK and pyruvate carboxylase, and for effects of bST, suggesting that glucocorticoid status is important.
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Affiliation(s)
- H M Hammon
- Division of Nutrition and Physiology, Institute of Animal Genetics, Nutrition and Housing, Vetsuisse Faculty, University of Berne, CH-3012 Berne, Switzerland.
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11
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Donkin S, Hammon H. Chapter 15 Hepatic gluconeogenesis in developing ruminants. BIOLOGY OF GROWING ANIMALS 2005. [DOI: 10.1016/s1877-1823(09)70022-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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12
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Agca C, Greenfield RB, Hartwell JR, Donkin SS. Cloning and characterization of bovine cytosolic and mitochondrial PEPCK during transition to lactation. Physiol Genomics 2002; 11:53-63. [PMID: 12388798 DOI: 10.1152/physiolgenomics.00108.2001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cytosolic (C) and mitochondrial (M) forms of phosphoenolpyruvate carboxykinase (PEPCK; EC 4.1.1.32) are encoded by two different nuclear genes in mouse, human, and chicken. Our objective was to clone the two forms of PEPCK for bovine and determine their expression during the immediate periparturient interval in dairy cows. Bovine PEPCK-C cDNA contains 2,592 nucleotides and contains 84% similarity to the coding sequence of human PEPCK-C cDNA. A 449-nt partial clone of the 3' end of PEPCK-M is 76% similar to the corresponding sequence of human PEPCK-M. The coding sequence of bovine PEPCK-C and coding sequence of the partial PEPCK-M clone were 58% similar but the similarities in the 3'-untranslated regions were negligible. Northern blot analysis revealed single transcripts of 2.85 and 2.35 kb for PEPCK-C and PEPCK-M, respectively. The transition to lactation did not alter PEPCK-M transcript expression, but expression of PEPCK-C mRNA was transiently increased during early lactation, indicating that enhanced hepatic gluconeogenesis during this period may be tied to enhanced capacity for cytosolic rather than mitochondrial formation of phosphoenolpyruvate.
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Affiliation(s)
- Cansu Agca
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana 47906, USA
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13
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Greenfield RB, Cecava MJ, Donkin SS. Changes in mRNA expression for gluconeogenic enzymes in liver of dairy cattle during the transition to lactation. J Dairy Sci 2000; 83:1228-36. [PMID: 10877388 DOI: 10.3168/jds.s0022-0302(00)74989-7] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The objective of this study was to profile phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate carboxylase (PC) mRNA expression in the liver of dairy cattle during the peripartum transition and determine changes in abundance of these mRNA in response to protein fed during the prepartum period. Thirty-eight multiparous Holstein cows were fed diets containing either 12% crude protein (CP) and 26% rumen undegradable protein (RUP), 16% CP and 26% RUP, 16% CP and 33% RUP, or 16% CP and 40% RUP on a dry-matter basis beginning 28 d before expected calving. After calving, all cows were fed a common diet through 56 d in milk (DIM). Northern analysis of RNA from liver biopsy samples obtained on days -28, -14, +1, +28, and +56 relative to calving indicated that PC and PEPCK mRNA expression were responsive to onset of lactation but not to prepartum protein or RUP concentration. Abundance of PEPCK mRNA was similar at -28, -14, and +1 DIM but was elevated by +28 and +56 DIM relative to precalving levels. Liver PC mRNA abundance was elevated on +1 DIM, remained elevated through 28 DIM, and declined to precalving levels by 56 DIM. The activity of PC enzyme was correlated (r2 = 0.89) with PC mRNA abundance. The data demonstrate increased abundance of PC mRNA during the early transition period followed by increased abundance of PEPCK mRNA during the postpartum period and suggest increased potential metabolism of lactate, pyruvate, and amino acids that contribute to the liver pyruvate pool.
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Affiliation(s)
- R B Greenfield
- Department of Animal Science, Purdue University, West Lafayette, IN 47906, USA
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14
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She P, Lindberg GL, Hippen AR, Beitz DC, Young JW. Regulation of messenger ribonucleic acid expression for gluconeogenic enzymes during glucagon infusions into lactating cows. J Dairy Sci 1999; 82:1153-63. [PMID: 10386301 DOI: 10.3168/jds.s0022-0302(99)75338-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effects of glucagon infusions on expression of mRNA for enzymes that regulate gluconeogenesis were studied in lactating cows. Normal cows and cows with fatty liver that were susceptible to ketosis were assigned to either glucagon-treated or control groups. Glucagon at 0 or 10 mg/d was infused for 14 d beginning at d 21 postpartum. In normal cows, glucagon infusions increased concentrations of both plasma glucagon and glucose, which caused plasma insulin to increase. Consequently, hepatic phosphoenolpyruvate carboxykinase mRNA decreased during wk 1 of glucagon infusions. Glucagon infusions into cows with fatty liver also increased plasma glucagon and glucose, but concentrations of plasma insulin and hepatic phosphoenolpyruvate carboxykinase mRNA did not change. More phosphoenolpyruvate carboxykinase mRNA was present in the livers of cows with fatty liver than in livers of normal cows. In a follow-up experiment with midlactation cows, 3.5-h infusions of glucagon at 14 mg/d increased plasma glucose and insulin and decreased plasma nonesterified fatty acids and hepatic glycogen. Hepatic phosphoenolpyruvate carboxykinase mRNA was decreased 41%, pyruvate carboxylase mRNA was increased 50%, but fructose-1,6-bisphosphatase mRNA did not change. We conclude that the expression of the hepatic phosphoenolpyruvate carboxykinase gene in normal cows is inhibited by insulin to balance elevated carbohydrate status during glucagon infusions; however, inhibited expression of hepatic phosphoenolpyruvate carboxykinase mRNA probably is not involved in the pathogenesis of lactation ketosis.
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Affiliation(s)
- P She
- Department of Animal Science, Iowa State University, Ames 50011-3150, USA
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15
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Abstract
Pyruvate carboxylase (PC; EC 6.4.1.1), a member of the biotin-dependent enzyme family, catalyses the ATP-dependent carboxylation of pyruvate to oxaloacetate. PC has been found in a wide variety of prokaryotes and eukaryotes. In mammals, PC plays a crucial role in gluconeogenesis and lipogenesis, in the biosynthesis of neurotransmitter substances, and in glucose-induced insulin secretion by pancreatic islets. The reaction catalysed by PC and the physical properties of the enzyme have been studied extensively. Although no high-resolution three-dimensional structure has yet been determined by X-ray crystallography, structural studies of PC have been conducted by electron microscopy, by limited proteolysis, and by cloning and sequencing of genes and cDNA encoding the enzyme. Most well characterized forms of active PC consist of four identical subunits arranged in a tetrahedron-like structure. Each subunit contains three functional domains: the biotin carboxylation domain, the transcarboxylation domain and the biotin carboxyl carrier domain. Different physiological conditions, including diabetes, hyperthyroidism, genetic obesity and postnatal development, increase the level of PC expression through transcriptional and translational mechanisms, whereas insulin inhibits PC expression. Glucocorticoids, glucagon and catecholamines cause an increase in PC activity or in the rate of pyruvate carboxylation in the short term. Molecular defects of PC in humans have recently been associated with four point mutations within the structural region of the PC gene, namely Val145-->Ala, Arg451-->Cys, Ala610-->Thr and Met743-->Thr.
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Affiliation(s)
- S Jitrapakdee
- Department of Biochemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
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16
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Vernon RG, Faulkner A, Finley E, Watt PW, Zammit VA. Effects of prolonged treatment of lactating goats with bovine somatotropin on aspects of adipose tissue and liver metabolism. J DAIRY RES 1995; 62:237-48. [PMID: 7601971 DOI: 10.1017/s0022029900030946] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of prolonged (22 weeks) treatment of lactating goats with bovine somatotropin on the metabolism of adipose tissue and liver has been investigated. Somatotropin treatment resulted in smaller adipocytes, decreased rate of fatty acid synthesis and decreased total acetyl-CoA carboxylase activity of adipocytes, but with no change in the proportion of this enzyme in the active state. The rate of acylglycerol glycerol synthesis from glucose of adipocytes tended to decrease as did total glucose utilization by the tissue. Glucose conversion to lactate was unchanged by somatotropin treatment but glucose conversion to other products was decreased. Maximum response of adipose tissue to insulin was unchanged but the sensitivity to insulin decreased on somatotropin treatment. Treatment with somatotropin had no effect on basal lipolysis and decreased maximum response to the beta-agonist isoproterenol, but this probably reflects the rate of isoproterenol-stimulated lipolysis varying with cell volume in adipocytes. No apparent change in response either to alpha 2-adrenergic agonists or to adenosine was apparent. The number of beta-adrenergic receptors was unchanged in adipocyte membranes but the number of alpha 2-adrenergic receptors increased. The rate of hepatic gluconeogenesis in vitro, the activity of key gluconeogenic enzymes and the modulation of the rate of gluconeogenesis by butyrate were unchanged except for the effect of this latter agent on gluconeogenesis from propionate. Hepatic ketogenic activity, as indicated by the activity of carnitine palmitoyl-CoA-transferase-1 and the concentrations of carnitine and acyl carnitines, was unchanged by treatment. Thus at the end of a prolonged period of treatment with somatotropin in lactating goats, lipid synthesis in adipose tissue is still decreased but no effects on liver lipid and carbohydrate metabolism were apparent.
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17
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Herdt TH, Emery RS. Therapy of diseases of ruminant intermediary metabolism. Vet Clin North Am Food Anim Pract 1992; 8:91-106. [PMID: 1555119 DOI: 10.1016/s0749-0720(15)30761-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Diseases of intermediary metabolism include ketosis and fatty liver of dairy cattle and pregnancy toxemia of ewes. These conditions occur when there is a failure of the homeostatic mechanisms regulating the mobilization of fats and the conservation of carbohydrates. The therapeutic approach is to reestablish the normal homeostatic patterns of fuel utilization. Suppression of excessive ketogenesis is the most important factor in reestablishing homeostasis. Ketogenesis can be suppressed by a number of therapeutic agents that act either by suppressing the mobilization of fatty acids or by inhibiting the transport of fatty acids into the hepatic mitochondria, the site at which fatty acids are converted to ketone bodies. Useful therapies include bolus glucose infusions, glucose precursors, and glucocorticoids.
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Affiliation(s)
- T H Herdt
- Michigan State University College of Veterinary Medicine, East Lansing
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18
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Abstract
The effects of insulin on the utilization of propionate in glucose synthesis were studied in fed and fasted sheep. Insulin was infused at 0.40 microU/h into the mesenteric vein. Glucose was infused to prevent hypoglycaemia. The rate of incorporation of [2-14C]propionate into glucose was determined before and during insulin infusion. After 150 min of insulin infusion endogenous glucose synthesis was about 70% of control values, whereas the incorporation of [14C]propionate into plasma glucose was 94% of control values. In contrast, the incorporation of other glucose precursors into glucose was decreased 30-50% by insulin. Therefore, insulin does not appear to decrease the utilization of propionate in gluconeogenesis. These results are consistent with the proposition that insulin differentially affects the rate of incorporation of glucose precursors into glucose in ruminant animals.
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Affiliation(s)
- R P Brockman
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Canada
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Garcia-Salguero L, Lupiañez JA. Long term control of renal carbohydrate metabolism--I. Effect of starve-feed cycles on renal tubules gluconeogenesis. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1988; 20:943-50. [PMID: 2848733 DOI: 10.1016/0020-711x(88)90179-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. Adaptive responses of renal gluconeogenesis to alternative starve-feed cycles in isolated kidney tubules are reported. 2. An increase of renal gluconeogenesis during the starve state of the cycles took place, reaching values between 1.7 and 3.2-fold in the starve-feed and feed-starve cycles respectively. 3. Conversely, a decrease in this metabolic pathway took place during the feed state of the cycles. During the feed-starve cycle the decrease reached 70% whereas in the opposite cycle it was almost 60%. 4. The activities of renal gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and fructose 1,6-bisphosphatase are parallel to the gluconeogenic capacity throughout the different nutritional conditions although different regulating mechanisms appear in both enzymes. 5. Phosphoenolpyruvate carboxykinase changed its activity at all substrate concentrations without significant changes in Km values during the development of the nutritional cycles, whereas fructose 1,6-bisphosphatase activity only varied at subsaturating substrate concentrations with modifications in the Km values for fructose 1,6-bisphosphate in these nutritional conditions.
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Affiliation(s)
- L Garcia-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencìas, Universidad de Granada, Spain
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Abstract
Heterogeneity of metabolic activity along the nephron points to a very varied relationship between glucose metabolism and ion transport. Glycolysis is linked closely to free-water clearance and possibly to sodium, potassium, and hydrogen ion transport. Glucose oxidation, while not the major source of renal energy, is crucial in sodium, potassium, and phosphate reabsorption. Gluconeogenesis recovers carbon compounds generated during the process of renal ammoniagenesis. Glucose synthesis and active sodium transport appear to compete for renal ATP, although no regulatory function for this competition has been identified. Glucose formed in the proximal tubule may support free-water clearance in adjacent distal tubule, but is not thought to contribute to any medullary function. The complex network of biosynthetic and catabolic pathways of glucose metabolism may have evolved in the kidney to protect the organism against wide variations in glucose demand which would otherwise be unavoidable during the course of rapidly fluctuating renal electrolyte loads.
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Gill W, Mitchell GE, Boling JA, Tucker RE, Schelling GT, DeGregorio RM. Glucagon influence on gluconeogenesis and oxidation of propionic acid and threonine by perfused ovine liver. J Dairy Sci 1985; 68:2886-94. [PMID: 3935699 DOI: 10.3168/jds.s0022-0302(85)81182-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An in situ ovine liver perfusion technique was developed and used to study glucagon effects on utilization of simultaneously infused propionic acid and amino acids. Physiological amounts of propionic acid and amino acids (hydrolyzed casein) were infused into livers along with carbon-14 propionic acid or carbon-14 threonine with and without glucagon. Glucagon (5 mg) caused a 75% increase of glucose synthesis and a 19% increase of labeled carbon dioxide production from carbon-14 propionic acid. There also was a decrease of perfusate urea nitrogen when glucagon was present. Glucagon caused a 76% decrease of carbon-14 threonine utilization by ovine livers, and labeled carbon dioxide production from carbon-14 threonine was only 38% of control when glucagon was infused. From these results, glucagon caused an increase of use of propionic acid and a decrease of use of threonine for energetic pathways in sheep liver. Therefore, glucagon directly or indirectly may mediate amino acid sparing by ruminant liver.
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Mohan C, Bessman SP. Anabolic regulation of gluconeogenesis by insulin in isolated rat hepatocytes. Arch Biochem Biophys 1985; 242:563-73. [PMID: 3904628 DOI: 10.1016/0003-9861(85)90244-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The role of substrate availability in the regulation of gluconeogenesis in isolated rat hepatocytes was studied using [U-14C]alanine as a tracer in the presence of different concentrations of L-alanine in the incubation medium. At low alanine concentrations (0.5 mM) insulin decreased the 14C incorporation into the glucose pool and increased the incorporation of tracer carbons into the protein and lipid pools and into CO2. The net radioactivity lost from the glucose pool was only a small percentage of the total increase in the activity of the protein, lipid, CO2, or glycogen pools, supporting the notion that the effect of insulin in diminishing gluconeogenesis is secondary to its effects on pathways using pyruvate. At higher concentrations of alanine (2.5, 5.0, and 10.0 mM) in the incubation medium insulin increased the movement of alanine carbons into protein and glucose. This suggests that at higher substrate concentrations the ability of the liver to synthesize proteins is overwhelmed and the pyruvate carbons are forced into the gluconeogenesis pathway. These results were further confirmed by using [U-14C]lactate. The increases in observed specific activity of glucose following insulin administration would not be possible if insulin acted by affecting the activity of any enzyme directly involved in the formation or utilization of pyruvate, most of which have been proposed as sites of insulin action. Data presented show that insulin "inhibits" gluconeogenesis by affecting a change in substrate availability.
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Hamada T, Matsumoto M. Effects of nutrition and ontogeny on liver cytosolic and mitochondrial phosphoenolpyruvate carboxykinase activity of the rat, hamster, guinea-pig, pig, kid, calf and chick. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1984; 77:547-50. [PMID: 6713828 DOI: 10.1016/0305-0491(84)90273-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In rat, hamster, guinea-pig, pig, kid, and calf liver, starvation or carbohydrate starvation increased cytosolic phosphoenolpyruvate carboxykinase activity without changing the mitochondrial activity whereas in chick liver, starvation did not alter the activity in both fractions. Liver glycogen content changed in a reciprocal way to the cytosolic phosphoenolpyruvate carboxykinase activity. In prenatal kid and chick liver, phosphoenolpyruvate carboxykinase activity appeared in both cytosolic and mitochondrial fractions, and in chick liver, considerable increase of the cytosolic activity was observed from a few days before hatching to 4 days after hatching.
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Mohan C, Bessman SP. Insulin "inhibition" of gluconeogenesis by stimulation of protein synthesis. BIOCHEMICAL MEDICINE 1981; 26:403-26. [PMID: 7036991 DOI: 10.1016/0006-2944(81)90016-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Weinberg MB, Utter MF. Effect of streptozotocin-induced diabetes mellitus on the turnover of rat liver pyruvate carboxylase and pyruvate dehydrogenase. Biochem J 1980; 188:601-8. [PMID: 7470023 PMCID: PMC1161940 DOI: 10.1042/bj1880601] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Immunochemical techniques were used to study the effect of streptozotocin-induced diabetes on the amounts of pyruvate carboxylase and pyruvate dehydrogenase and on their rates of synthesis and degradation. Livers from diabetic rats had twice the pyruvate carboxylase activity of livers from normal rats when expressed in terms of DNA or body weight. The changes in catalytic activity closely paralleled changes in immunoprecipitable enzyme protein. Relative rates of synthesis determined by pulse-labelling studies showed that the ratio of synthesis of pyruvate carboxylase to that of average mitochondrial protein was increased 2.0-2.5 times in diabetic animals over that of control animals. Other radioisotopic studies indicated that the rate of degradation of this enzyme was not altered significantly in diabetic rats, suggesting that the increase in this enzyme was due to an increased rate of synthesis. Similar experiments with pyruvate dehydrogenase, the first component of the pyruvate dehydrogenase complex, showed that livers from diabetic rats had approximately the same amount of immunoprecipitable enzyme protein as the control animals, but a larger proportion of the enzyme was in its inactive state. The rates of synthesis and degradation of pyruvate dehydrogenase were not affected significantly by diabetes.
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Moose PR. An investigation of gluconeogenesis in marine teleosts, and the effect of long-term exercise on hepatic gluconeogenesis. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0305-0491(80)90418-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Mörikofer-Zwez S, Walter P. In vitro formation of glucose-6-phosphate from glyceraldehyde-3-phosphate by liver cytosol from fed and starved rats. Effect of divalent cations on the conversion rate. Biochem Biophys Res Commun 1979; 91:1182-9. [PMID: 118752 DOI: 10.1016/0006-291x(79)92004-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Shen CS, Mistry SP. Effect of fasting and fasting and refeeding on hepatic and renal gluconeogenic enzymes in the chicken. Poult Sci 1979; 58:890-5. [PMID: 226947 DOI: 10.3382/ps.0580890] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The effect of fasting and fasting and refeeding on hepatic and renal gluconeogenic enzyme activities were studied in six-week-old chickens (Gallus domesticus: New Hampshire male x Columbian female). Hepatic pyruvate carboxylase appeared not to be affected by fasting, but the renal enzyme activity increased in four-day fasted chickens. The hepatic mitochondrial and cytosolic phosphoenolpyruvate carboxykinases were essentially not affected by fasting. The renal mitochondrial phosphoenolpyruvate carboxykinase showed a slight increase in activity only after a four-day fast, but the cytosolic enzyme activity increased markedly already after a two-day fast. Also the activities of the hepatic and renal fructose-1,6-diphosphatase and glucose-6-phosphatase increased markedly on fasting. Refeeding for four days after a four-day fast returned these enzyme activities to near control values.
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Zaleski J, Bryła J. Effect of alloxan-diabetes on gluconeogenesis and ureogenesis in isolated rabbit liver cells. Biochem J 1978; 176:563-8. [PMID: 743258 PMCID: PMC1186265 DOI: 10.1042/bj1760563] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. Neither alloxan-diabetes nor starvation affected the rate of glucose production in hepatocytes incubated with lactate, pyruvate, propionate or fructose as substrates. In contrast, glucose synthesis with either alanine or glutamine was increased nearly 3- and 12-fold respectively, in comparison with that in fed rabbits. 2. The addition of amino-oxyacetate resulted in about a 50% decrease in glucose formation from lactate in hepatocytes isolated from fed, alloxan-diabetic and starved rats, suggesting that both mitochondrial and cytosolic forms of rabbit phosphoenolpyruvate carboxykinase function actively during gluconeogenesis. 3. Alloxan-diabetes resulted in about 2-3-fold stimulation of urea production from either amino acid studied or NH4Cl as NH3 donor, whereas starvation caused a significant increase in the rate of ureogenesis only in the presence of alanine as the source of NH3. 4. As concluded from changes in the [3-hydroxybutyrate]/[acetoacetate] ratio, in hepatocytes from diabetic animals the mitochondrial redox state was shifted toward oxidation in comparison with that observed in liver cells isolated from fed rabbits.
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Hove K. Maintenance of lactose secretion during acute insulin deficiency in lactating goats. ACTA PHYSIOLOGICA SCANDINAVICA 1978; 103:173-9. [PMID: 676768 DOI: 10.1111/j.1748-1716.1978.tb06205.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Induction of alloxan diabetes in 5 lactating goats resulted in reduced milk yields in 3 of the animals, while the yield was unchanged in two. After treatment of the diabetic goats with insulin for 4--5 days--the last 24 h intravenously--lactose secretion returned to the control values before alloxan administration provided that normoglycemia developed. In 2 experiments infusion of a large dose of insulin caused hypoglycemia and a 20--30 per cent reduction in lactose secretion rates. In the course of 1 h after withdrawal of the insulin infusion, patent signs of insulin deficiency developed as evidenced by steadily increasing plasma glucose concentrations. Nevertheless, lactose secretion continued at the same rate as during insulin infusion for the 4 h studied after discontinuation of the insulin infusion. In the goats where lactose secretion was reduced due to insulin-induced hypoglycemia, lactose secretion returned to control values when following discontinuation of insulin infusion the plasma glucose concentrations increased into normal and diabetic ranges. It is concluded that during insulin deficiency of short term duration, mammary lactose secretion was maintained at a normal rate. Since lactose is the major product of mammary glucose utilization, it is suggested that glucose uptake in the mammary gland was not reduced by short term insulin deficiency.
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Prior RL, Scott RA. Ontogeny of gluconeogenesis in the bovine fetus: influence of maternal dietary energy. Dev Biol 1977; 58:384-93. [PMID: 195854 DOI: 10.1016/0012-1606(77)90099-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Gluconeogenesis is a continual process that is of great importance in ruminants because almost all dietary carbohydrates are fermented to volatile fatty acids in the rumen. In turn, propionate is the only major volatile fatty acid that contributes to gluconeogenesis. Many different techniques and analytical procedures are involved in studying ruminant gluconeogenesis. Glucose kinetics can be examined by single-injection or continuous-infusion isotope dilution techniques with a variety of glucose labels. Correcting for recycling of label is an important consideration. Absorption of glucose from the gut can be measured by combining arterial-venous differences and flow rates of portal blood or can be estimated by determining the amount of glucose plus alpha-glucose polymers passing into the small intestine. Production of propionate in the ruminoreticulum can be measured by isotope dilution techniques. Quantitating the conversion of propionate to glucose requires the use of [carbon-14]propionate with careful corrections for propionate carbon entering the citric acid cycle before incorporation into glucose; The same fundamental techniques used with propionate are required to quantitate the contributions of amino acids and other precursors to glucose. In vitro studies of gluconeogenic enzymes, and cellular, tissue, or organ preparations provide valuable insights into the gluconeogenic processes and controls but must be validated by in vivo experiments. Progress has been considerable in understanding some aspects of ruminant gluconeogenesis, but many more studies will be required to obtain a complete understanding.
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Head HH, Thatcher WW, Wilcox CJ, Bachman KC. Effect of a synthetic corticoid on milk yield and composition and on blood metabolites and hormones in dairy cows. J Dairy Sci 1976; 59:880-8. [PMID: 1270650 DOI: 10.3168/jds.s0022-0302(76)84292-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Twenty-five dairy cows were assigned randomly by breed to flumethasone treatment (10 mug/day, 13 cows) or placebo control (12 cows) from 4 to 44 wk of lactation. Lactation means and trends with stage of lactation were treatment responses. Mean milk yields of cows supplemented with flumethasone were not significantly different from controls. Mean metabolite (glucose, nonesterified fatty acids, and total esterified fatty acids) and hormone concentrations (corticoids, insulin, and prolactin) of blood plasma and their trends throughout lactation were unaffected by supplementation. Data were pooled to determine effects of stage of lactation, temperature, pregnancy, and month on these variables. Changes during lactation were systematic for feed intake, body weight, milk yield, milk components except somatic cells, blood metabolites, and prolactin. At environmental temperatures above 18 C, effects were consistently negative for milk yield and composition, but only above 26 C for feed intake. Prolactin of plasma increased with increasing temperature to 18.2 C and then decreased. No other plasma metabolite or hormone was affected by days pregnant, age, or temperature. Months affected feed intake, milk yield, milk fat percentages, all blood metabolites, and prolactin. Prolactin concentrations increased as daylight hours increased. Our inability to augment established lactation by feeding a supplement of synthetic glucocorticoid to lactating cows is consistent with the view that a lack of avialable corticoids does not limit persistency of lactation in the cow.
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Huston RL, Weiser PC, Dohm GL, Askew EW, Boyd JB. Effects of training, exercise and diet on muscle glycolysis and liver gluconeogenesis. Life Sci 1975; 17:369-76. [PMID: 125836 DOI: 10.1016/0024-3205(75)90486-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Rabinowitz L, Gunther RA, Shoji ES, Freedland RA, Avery EH. Effects of high and low protein diets on sheep renal function and metabolism. Kidney Int 1973; 4:188-207. [PMID: 4750911 DOI: 10.1038/ki.1973.101] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Judson GJ, Leng RA. Studies on the control of gluconeogenesis in sheep: effect of glucose infusion. Br J Nutr 1973; 29:159-74. [PMID: 4693554 DOI: 10.1079/bjn19730092] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
1. Effect of glucose infusions on the rate of gluconeogenesis, as indicated by changes in the irreversible loss of plasma glucose, synthesis of glucose from ruminal propionate or fixation of blood bicarbonate into glucose, has been examined in sheep.Sheep, feeding at hourly intervals, received intravenous infusions of [U-14C]glucose, NaH14CO3, or [6-3H]glucose, infused simultaneously with an intraruminal infusion of [2-14C]propionate. Glucose (4–144 mg/min) was infused intravenously at a single rate or at two different successive rates of equal duration. The glucose infusions were over a 6 h period and followed estimates of pre-infusion kinetic measurements.2. The infusion of glucose suppressed endogenous glucose production in direct proportion to that infused for sheep given diets of lucrene or wheat. The maximum rate of suppression recorded was equivalent to about 50–60% of the endogenous production rate of glucose.Transfer rates of carbon-14 from blood bicarbonate or ruminal propionate to plasma glucose were reduced during glucose loadings. The results indicate that administration of glucose was more effective in suppressing the synthesis of glucose from substrates other than ruminal propionate.3. The percentage of glucose carbon derived from blood bicarbonate was lower in sheep given wheat than in sheep given lucerne. It was suggested that this difference may have been due to absorption of glucose from the alimentary canal of sheep on the former ration. Approximately 8% of the wheat starch may have escaped fermentation and been absorbed as glucose in these animals.
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Baird GD, Heitzman RJ, Hibbitt KG. Effects of starvation on intermediary metabolism in the lactating cow. A comparison with metabolic changes occurring during bovine ketosis. Biochem J 1972; 128:1311-8. [PMID: 4345357 PMCID: PMC1174019 DOI: 10.1042/bj1281311] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. The purpose of this study was to determine the nature of the metabolic changes associated with carbohydrate and fat metabolism that occurred in the blood and liver of lactating dairy cows during starvation for 6 days. 2. During starvation, the blood concentrations of the free fatty acids and ketone bodies increased, whereas that of citrate decreased. After an initial increase, the blood concentration of glucose subsequently declined as starvation progressed. Starvation caused a significant decrease in the plasma concentration of serine and a significant increase in that of leucine. 3. After 6 days of starvation the hepatic concentrations of oxaloacetate, citrate, phosphoenolpyruvate, 2-phosphoglycerate, 3-phosphoglycerate, glucose, glycogen, ATP and NAD(+) had all decreased, as had the hepatic activities of phosphopyruvate carboxylase (EC 4.1.1.32) and pyruvate kinase (EC 2.7.1.40). 4. The above metabolic changes are similar to those previously found to occur in cows suffering from spontaneous ketosis (Baird et al., 1968; Baird & Heitzman, 1971). 5. Milk yield decreased progressively during starvation. 6. There were marked differences in the ability of individual animals to resist the onset of severe starvation ketosis.
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Barns RJ, Keech DB. Sheep kidney phosphoenolpyruvate carboxylase. Purification and properties. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 276:284-96. [PMID: 5047708 DOI: 10.1016/0005-2744(72)90031-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Butler TM, Elliot JM. Effect of diet and glucocorticoid administration of liver phosphoenolpyruvate carboxykinase activity in the dairy cow. J Dairy Sci 1970; 53:1727-33. [PMID: 5530980 DOI: 10.3168/jds.s0022-0302(70)86470-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wimhurst JM, Manchester KL. A comparison of the effects of diabetes induced with either alloxan or streptozotocin and of starvation on the activities in rat liver of the key enzymes of gluconeogenesis. Biochem J 1970; 120:95-103. [PMID: 4321934 PMCID: PMC1179572 DOI: 10.1042/bj1200095] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. Measurements of the activities in rat liver of the four key enzymes involved in gluconeogenesis, i.e. pyruvate carboxylase (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (EC 4.1.1.32), fructose 1,6-diphosphatase (EC 3.1.3.11) and glucose 6-phosphatase (EC 3.1.3.9), have been carried out, all four enzymes being measured in the same liver sample. Changes in activities resulting from starvation and diabetes have been studied. Changes in concentration (activity/unit wet weight of tissue) were compared with changes in the hepatic cellular content (activity/unit of DNA). 2. Each enzyme was found to increase in concentration during starvation for up to 3 days, but only glucose 6-phosphatase and phosphoenolpyruvate carboxykinase showed a significant rise in content. Fructose 1,6-diphosphatase appeared to decrease in content somewhat during the early stages of starvation. 3. There was a marked increase in the concentration of all four enzymes in non-starved rats made diabetic with alloxan or streptozotocin, for the most part similar responses being found for the two diabetogenic agents. On starvation, however, the enzyme contents in the diabetic animals tended to fall, often with streptozotocin-treated animals to values no greater than for the normal overnight-starved rat. Deprivation of food during the period after induction of diabetes with streptozotocin lessened the rise in enzyme activity. 4. The results are compared with other published values and factors such as substrate and activator concentrations likely to influence activity in vivo are considered. 5. Lack of correlation of change in fructose 1,6-diphosphatase with the other enzymes questions whether it should be included in any postulation of control of gluconeogenic enzymes by a single gene unit.
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Wimhurst JM, Manchester KL. Suppression of pyruvate carboxylase by glucose in the perfused rat liver. FEBS Lett 1970; 8:91-94. [PMID: 11947539 DOI: 10.1016/0014-5793(70)80232-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- J M. Wimhurst
- Department of Biochemistry, University College London, Gower Street, WC1E 6BT, London, UK
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Sabine JR, Morris HP. Control of glucose metabolism in transplantable kidney tumours: low gluconeogenesis by tumours MK-I and MK-2. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 208:203-7. [PMID: 5420973 DOI: 10.1016/0304-4165(70)90238-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Baird GD, Heitzman RJ. Gluconeogenesis in the cow. The effects of a glucocorticoid on hepatic intermediary metabolism. Biochem J 1970; 116:865-74. [PMID: 4392535 PMCID: PMC1185509 DOI: 10.1042/bj1160865] [Citation(s) in RCA: 46] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. The hepatic concentrations of the ketone bodies and of metabolites and activities of enzymes involved in gluconeogenesis were measured in healthy lactating and non-lactating cows 48h after administration of Voren, an ester of dexamethasone, and compared with those found in control animals given saline. Parallel measurements were also made of the blood concentrations of several of the metabolites. 2. Blood glucose concentrations were raised in the Voren-treated animals, whereas blood ketone body and free fatty acid concentrations were unaltered. Similarly there was no change in the hepatic concentrations of the ketone bodies. 3. Significant increases were found in the hepatic concentrations of citrate, 2-oxo-glutarate and malate in both groups of animals given Voren. 4. The hepatic concentrations of those glycolytic intermediates that were measured either decreased or did not change after Voren treatment. 5. The enzymes aspartate transaminase and fructose 1,6-diphosphatase were unchanged in activity after Voren administration, whereas phosphopyruvate carboxylase (EC 4.1.1.32) activity was depressed in the lactating group. However, glucose 6-phosphatase, tryptophan oxygenase and tyrosine aminotransferase increased in activity. 6. In several cases those hepatic metabolites that increased in concentration after Voren administration were present in lower concentration in normal lactating cows than in normal non-lactating cows. The same applied mutatis mutandis to those metabolites that were decreased by Voren. 7. These findings are discussed in relation to the use of glucocorticoids in the treatment of bovine ketosis.
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