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Assis AP, Silva KE, Lautherbach N, Morgan HJN, Garófalo MAR, Zanon NM, Navegantes LCC, Chaves VE, Kettelhut IDC. Glucocorticoids decrease thermogenic capacity and increase triacylglycerol synthesis by glycerokinase activation in the brown adipose tissue of rats. Lipids 2022; 57:313-325. [PMID: 36098349 DOI: 10.1002/lipd.12358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/03/2022] [Accepted: 08/28/2022] [Indexed: 11/11/2022]
Abstract
Although it is well established that glucocorticoids inactivate thermogenesis and promote lipid accumulation in interscapular brown adipose tissue (IBAT), the underlying mechanisms remain unknown. We found that dexamethasone treatment (1 mg/kg) for 7 days in rats decreased the IBAT thermogenic activity, evidenced by its lower responsiveness to noradrenaline injection associated with reduced content of mitochondrial proteins, respiratory chain protein complexes, noradrenaline, and the β3 -adrenergic receptor. In parallel, to understand better how dexamethasone increases IBAT lipid content, we also investigated the activity of the ATP citrate lyase (ACL), a key enzyme of de novo fatty acid synthesis, glucose-6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme of the pentose phosphate pathway, and the three glycerol-3-P generating pathways: (1) glycolysis, estimated by 2-deoxyglucose uptake, (2) glyceroneogenesis, evaluated by phosphoenolpyruvate carboxykinase activity and pyruvate incorporation into triacylglycerol-glycerol, and (3) direct phosphorylation of glycerol, investigated by the content and activity of glycerokinase. Dexamethasone increased the mass and the lipid content of IBAT as well as plasma levels of glucose, insulin, non-esterified fatty acid, and glycerol. Furthermore, dexamethasone increased ACL and G6PD activities (79% and 48%, respectively). Despite promoting a decrease in the incorporation of U-[14 C]-glycerol into triacylglycerol (~54%), dexamethasone increased the content (~55%) and activity (~41%) of glycerokinase without affecting glucose uptake or glyceroneogenesis. Our data suggest that glucocorticoid administration reduces IBAT thermogenesis through sympathetic inactivation and stimulates glycerokinase activity and content, contributing to increased generation of glycerol-3-P, which is mostly used to esterify fatty acid and increase triacylglycerol content promoting IBAT whitening.
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Affiliation(s)
- Ana Paula Assis
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Karine Emanuelle Silva
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Natalia Lautherbach
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | | | - Neusa Maria Zanon
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | | | - Isis do Carmo Kettelhut
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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Buzelle SL, Przygodda F, Rossi-Valentim R, Ferreira GN, Garófalo MAR, Alves VM, Chaves VE, Navegantes LCC, Kettelhut IDC. Activation of adipose tissue glycerokinase contributes to increased white adipose tissue mass in mice fed a high-fat diet. Endocrine 2020; 69:79-91. [PMID: 32297203 DOI: 10.1007/s12020-020-02288-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/25/2020] [Indexed: 01/04/2023]
Abstract
PURPOSE Investigate the pathways of glycerol-3-P (G3P) generation for triacylglycerol (TAG) synthesis in retroperitoneal (RWAT) and epididymal (EWAT) white adipose tissues from high-fat diet (HFD)-fed mice. METHODS Mice were fed for 8 weeks a HFD and glycolysis, glyceroneogenesis and direct phosphorylation of glycerol were evaluated, respectively, by 2-deoxyglucose uptake, phosphoenolpyruvate carboxykinase (PEPCK-C) activity and pyruvate incorporation into TAG-glycerol, and glycerokinase activity and glycerol incorporation into TAG-glycerol in both tissues. RESULTS HFD increased body and adipose tissue mass and serum levels of glucose and insulin, which were accompanied by glucose intolerance. RWAT and EWAT from HFD-fed mice had increased rates of de novo fatty acid (FA) synthesis (52% and 255%, respectively). HFD increased lipoprotein lipase (LPL) activity and content in EWAT (107%), but decreased in RWAT (79%). HFD decreased the lipolytic response to norepinephrine (57%, RWAT and 25%, EWAT), β3-adrenoceptor content (50%), which was accompanied by a decrease in phosphorylated-hormone-sensitive lipase (~80%) and phosphorylated-adipocyte triacylglycerol lipase (~60%) in both tissues. HFD decreased the in vitro rates of glucose uptake (3.5- and 6-fold), as well as in glyceride-glycerol synthesis from pyruvate (~3.5-fold) without changes in PEPCK-C activity and content in RWAT and EWAT, but increased glycerokinase activity(~3-fold) and content (90 and 40%) in both tissues. CONCLUSION The data suggest that direct phosphorylation of glycerol by glycerokinase may be responsible for maintaining the supply of G3P for the existing rates of FA esterification and TAG synthesis in RWAT and EWAT from HFD-fed mice, contributing, along with a lower lipolytic response to norepinephrine, to higher adiposity.
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Affiliation(s)
- Samyra Lopes Buzelle
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Franciele Przygodda
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rafael Rossi-Valentim
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | | | - Vani Maria Alves
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Valéria Ernestânia Chaves
- Laboratory of Physiology, Federal University of São João del-Rei, Divinópolis, Minas Gerais, Brazil.
| | | | - Isis do Carmo Kettelhut
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Ferreira GN, Rossi-Valentim R, Buzelle SL, Paula-Gomes S, Zanon NM, Garófalo MAR, Frasson D, Navegantes LCC, Chaves VE, Kettelhut IDC. Differential regulation of glyceroneogenesis by glucocorticoids in epididymal and retroperitoneal white adipose tissue from rats. Endocrine 2017; 57:287-297. [PMID: 28555305 DOI: 10.1007/s12020-017-1315-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 04/29/2017] [Indexed: 01/03/2023]
Abstract
PURPOSE Investigate the glycerol-3-phosphate generation pathways in epididymal (EPI) and retroperitoneal (RETRO) adipose tissues from dexamethasone-treated rats. METHODS Rats were treated with dexamethasone for 7 days. Glycerol-3-phosphate generation pathways via glycolysis, glyceroneogenesis and direct phosphorylation of glycerol were evaluated, respectively, by 2-deoxyglucose uptake, phosphoenolpyruvate carboxykinase (PEPCK-C) activity and pyruvate incorporation into triacylglycerol (TAG)-glycerol, and glycerokinase activity and glycerol incorporation into TAG-glycerol. RESULTS Dexamethasone treatment markedly decreased the body weight, but increased the weight and lipid content of EPI and RETRO and plasma insulin, glucose, non-esterified fatty acid and TAG levels. EPI and RETRO from dexamethasone-treated rats showed increased rates of de novo fatty acid synthesis (80 and 100%) and basal lipolysis (20%). In EPI, dexamethasone decreased the 2-deoxyglucose uptake (50%), as well as glyceroneogenesis, evidenced by a decrease of PEPCK-C activity (39%) and TAG-glycerol synthesis from pyruvate (66%), but increased the glycerokinase activity (50%) and TAG-glycerol synthesis from glycerol (72%) in this tissue. In spite of a similar reduction in 2-deoxyglucose uptake in RETRO, dexamethasone treatment increased glyceroneogenesis, evidenced by PEPCK activity (96%), and TAG-glycerol synthesis from pyruvate (110%), accompanied by a decrease in glycerokinase activity (50%) and TAG-glycerol synthesis from glycerol (50%). Dexamethasone effects on RETRO were accompanied by a decrease in p-Akt content and by lower insulin effects on the rates of glycerol release in the presence of isoproterenol and on the rates of glucose uptake in isolated adipocytes. CONCLUSION Our data demonstrated differential regulation of glyceroneogenesis and direct phosphorylation of glycerol by glucocorticoids in EPI and RETRO from rats.
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Affiliation(s)
- Graziella Nascimento Ferreira
- Departments of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rafael Rossi-Valentim
- Departments of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Samyra Lopes Buzelle
- Biochemistry-Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sílvia Paula-Gomes
- Biochemistry-Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Neusa Maria Zanon
- Departments of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Danúbia Frasson
- Latin American Institute of Life and Nature Science, Federal University of Latin American Integration, Foz do Iguaçu, Paraná, Brazil
| | | | - Valéria Ernestânia Chaves
- Laboratory of Physiology, Federal University of São João del-Rei, Divinópolis, Minas Gerais, Brazil.
| | - Isis do Carmo Kettelhut
- Biochemistry-Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Ochi R, Kurotani K, Ikeda M, Kiyonaka S, Hamachi I. Supramolecular hydrogels based on bola-amphiphilic glycolipids showing color change in response to glycosidases. Chem Commun (Camb) 2012; 49:2115-7. [PMID: 23258236 DOI: 10.1039/c2cc37908b] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We developed supramolecular hydrogels exhibiting reversible thermochromism concurrently with gel-to-sol transition from four glycolipids. In addition, these gels showed the similar color change in response to glycosidases, which can be employed to construct a colorimetric sensor array chip for sensing glycosidases with the naked eye.
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Affiliation(s)
- Rika Ochi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, 615-8510, Japan
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Frasson D, Boschini RP, Chaves VE, dos Santos MESM, Paula Gomes SD, Valentim RR, Garófalo MAR, Navegantes LCC, Migliorini RH, Kettelhut IDC. The sympathetic nervous system regulates the three glycerol-3P generation pathways in white adipose tissue of fasted, diabetic and high-protein diet-fed rats. Metabolism 2012; 61:1473-85. [PMID: 22592131 DOI: 10.1016/j.metabol.2012.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/19/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
Abstract
The aim of the present study was to investigate the participation of the sympathetic nervous system (SNS) in the control of glycerol-3-P (G3P) generating pathways in white adipose tissue (WAT) of rats in three situations in which the plasma insulin levels are low. WAT from 48 h fasted animals, 3 day-streptozotocin diabetic animals and high-protein, carbohydrate-free (HP) diet-fed rats was surgical denervated and the G3P generation pathways were evaluated. Food deprivation, diabetes and the HP diet provoke a marked decrease in the rate of glucose uptake and glycerokinase (GyK) activity, but a significant increase in the glyceroneogenesis, estimated by the phosphoenolpyruvate carboxykinase (PEPCK) activity and the incorporation of 1-[(14)C]-pyruvate into glycerol-TAG. The denervation provokes a reduction (~70%) in the NE content of WAT in fasted, diabetic and HP diet-fed rats. The denervation induced an increase in WAT glucose uptake of fed, fasted, diabetic and HP diet-fed rats (40%, 60%, 3.2 fold and 35%, respectively). TAG-glycerol synthesis from pyruvate was reduced by denervation in adipocytes of fed (58%) and fasted (36%), saline-treated (58%) and diabetic (23%), and HP diet-fed rats (11%). In these same groups the denervation reduced the PEPCK mRNA expression (75%-95%) and the PEPCK activity (35%-60%). The denervation caused a ~35% decrease in GyK activity of control rats and a further ~35% reduction in the already low enzyme activity of fasted, diabetic and HP diet-fed rats. These data suggest that the SNS plays an important role in modulating G3P generating pathways in WAT, in situations where insulin levels are low.
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Affiliation(s)
- Danúbia Frasson
- Department of Biochemistry-Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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A low-protein, high-carbohydrate diet increases fatty acid uptake and reduces norepinephrine-induced lipolysis in rat retroperitoneal white adipose tissue. Lipids 2012; 47:279-89. [PMID: 22228227 DOI: 10.1007/s11745-011-3648-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 12/08/2011] [Indexed: 10/14/2022]
Abstract
A low-protein, high-carbohydrate (LPHC) diet for 15 days increased the lipid content in the carcass and adipose tissues of rats. The aim of this work was to investigate the mechanisms of this lipid increase in the retroperitoneal white adipose tissue (RWAT) of these animals. The LPHC diet induced an approximately two- and tenfold increase in serum corticosterone and TNF-α, respectively. The rate of de novo fatty acid (FA) synthesis in vivo was reduced (50%) in LPHC rats, and the lipoprotein lipase activity increased (100%). In addition, glycerokinase activity increased (60%), and the phosphoenolpyruvate carboxykinase content decreased (27%). Basal [U-¹⁴C]-glucose incorporation into glycerol-triacylglycerol did not differ between the groups; however, in the presence of insulin, [U-¹⁴C]-glucose incorporation increased by 124% in adipocytes from only control rats. The reductions in IRS1 and AKT content as well as AKT phosphorylation in the RWAT from LPHC rats and the absence of an insulin response suggest that these adipocytes have reduced insulin sensitivity. The increase in NE turnover by 45% and the lack of a lipolytic response to NE in adipocytes from LPHC rats imply catecholamine resistance. The data reveal that the increase in fat storage in the RWAT of LPHC rats results from an increase in FA uptake from circulating lipoproteins and glycerol phosphorylation, which is accompanied by an impaired lipolysis that is activated by NE.
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Jelen S, Wacker S, Aponte-Santamaría C, Skott M, Rojek A, Johanson U, Kjellbom P, Nielsen S, de Groot BL, Rützler M. Aquaporin-9 protein is the primary route of hepatocyte glycerol uptake for glycerol gluconeogenesis in mice. J Biol Chem 2011; 286:44319-25. [PMID: 22081610 DOI: 10.1074/jbc.m111.297002] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It has been hypothesized that aquaporin-9 (AQP9) is part of the unknown route of hepatocyte glycerol uptake. In a previous study, leptin receptor-deficient wild-type mice became diabetic and suffered from fasting hyperglycemia whereas isogenic AQP9(-/-) knock-out mice remained normoglycemic. The reason for this improvement in AQP9(-/-) mice was not established before. Here, we show increased glucose output (by 123% ± 36% S.E.) in primary hepatocyte culture when 0.5 mM extracellular glycerol was added. This increase depended on AQP9 because it was absent in AQP9(-/-) cells. Likewise, the increase was abolished by 25 μM HTS13286 (IC(50) ~ 2 μM), a novel AQP9 inhibitor, which we identified in a small molecule library screen. Similarly, AQP9 deletion or chemical inhibition eliminated glycerol-enhanced glucose output in perfused liver preparations. The following control experiments suggested inhibitor specificity to AQP9: (i) HTS13286 affected solute permeability in cell lines expressing AQP9, but not in cell lines expressing AQPs 3, 7, or 8. (ii) HTS13286 did not influence lactate- and pyruvate-dependent hepatocyte glucose output. (iii) HTS13286 did not affect glycerol kinase activity. Our experiments establish AQP9 as the primary route of hepatocyte glycerol uptake for gluconeogenesis and thereby explain the previously observed, alleviated diabetes in leptin receptor-deficient AQP9(-/-) mice.
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Affiliation(s)
- Sabina Jelen
- From the Water and Salt Research Center, Department of Biomedicine, Aarhus University, Wilhelm Meyers Allè, DK-8000 Aarhus C, Denmark
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Buzelle SL, Santos MP, Baviera AM, Lopes CF, Garófalo MAR, Navegantes LCC, Kettelhut IC, Chaves VE, Kawashita NH. A low-protein, high-carbohydrate diet increases the adipose lipid content without increasing the glycerol-3-phosphate or fatty acid content in growing rats. Can J Physiol Pharmacol 2011; 88:1157-65. [PMID: 21164562 DOI: 10.1139/y10-096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The amount of triacylglycerol (TAG) that accumulates in adipose tissue depends on 2 opposing processes: lipogenesis and lipolysis. We have previously shown that the weight and lipid content of epididymal (EPI) adipose tissue increases in growing rats fed a low-protein, high-carbohydrate (LPHC) diet for 15 days. The aim of this work was to study the pathways involved in lipogenesis and lipolysis, which ultimately regulate lipid accumulation in the tissue. De novo fatty acid synthesis was evaluated in vivo and was similar for rats fed an LPHC diet or a control diet; however, the LPHC-fed rats had decreased lipoprotein lipase activity in the EPI adipose tissue, which suggests that there was a decreased uptake of fatty acids from the circulating lipoproteins. The LPHC diet did not affect synthesis of glycerol-3-phosphate (G3P) via glycolysis or glyceroneogenesis. Glycerokinase activity - i.e., the phosphorylation of glycerol from the hydrolysis of endogenous TAG to form G3P - was also not affected in LPHC-fed rats. In contrast, adipocytes from LPHC animals had a reduced lipolytic response when stimulated by norepinephrine, even though the basal adipocyte lipolytic rate was similar for both of the groups. Thus, the results suggest that the reduction of lipolytic activity stimulated by norepinephrine seems essential for the TAG increase observed in the EPI adipose tissue of LPHC animals, probably by impairment of the process of activation of lipolysis by norepinephrine.
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Affiliation(s)
- Samyra L Buzelle
- Department of Chemistry, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil
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Festuccia WT, Blanchard PG, Turcotte V, Laplante M, Sariahmetoglu M, Brindley DN, Richard D, Deshaies Y. The PPARgamma agonist rosiglitazone enhances rat brown adipose tissue lipogenesis from glucose without altering glucose uptake. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1327-35. [PMID: 19211718 DOI: 10.1152/ajpregu.91012.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We investigated the mechanisms whereby peroxisome proliferator-activated receptor-gamma (PPARgamma) agonism affects glucose and lipid metabolism in brown adipose tissue (BAT) by studying the impact of PPARgamma activation on BAT glucose uptake and metabolism, lipogenesis, and mRNA levels plus activities of enzymes involved in triacylglycerol (TAG) synthesis. Interscapular BAT of rats treated or not with rosiglitazone (15 mg*kg(-1).day(-1), 7 days) was evaluated in vivo for glucose uptake and lipogenesis and in vitro for glucose metabolism, gene expression, and activities of glycerolphosphate acyltransferase (GPAT), phosphatidate phosphatase-1 (PAP or lipin-1), and diacylglycerol acyltransferase (DGAT). Rosiglitazone increased BAT mass without affecting whole tissue glucose uptake. BAT glycogen content (-80%), its synthesis from glucose (-50%), and mRNA levels of UDP-glucose pyrophosphorylase (-40%), which generates UDP-linked glucose for glycogen synthesis, were all reduced by rosiglitazone. In contrast, BAT TAG-glycerol synthesis in vivo and glucose incorporation into TAG-glycerol in vitro were stimulated by the agonist along with the activities and mRNA levels of glycerol 3-phosphate-generating phosphoenolpyruvate carboxykinase and glycerokinase. Furthermore, rosiglitazone markedly increased the activities of GPAT and DGAT but not those of lipin-1-mediated PAP-1, enzymes involved in the sequential acylation of glycerol 3-phosphate and TAG synthesis. Because an adequate supply of fatty acids is essential for BAT nonshivering thermogenesis, the enhanced ability of BAT to synthesize TAG under PPARgamma activation may constitute an important mechanism by which lipid substrates are stored in preparation for an eventual thermogenic activation.
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Affiliation(s)
- William T Festuccia
- Laval Hospital Research Centre and Department of Anatomy and Physiology, Faculty of Medicine, Laval University, Quebec, QC, Canada G1V 4G5
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Chaves VE, Frasson D, Martins-Santos MES, Navegantes LCC, Galban VD, Garófalo MAR, Kettelhut IC, Migliorini RH. Fatty acid synthesis and generation of glycerol-3-phosphate in brown adipose tissue from rats fed a cafeteria diet. Can J Physiol Pharmacol 2008; 86:416-23. [PMID: 18641690 DOI: 10.1139/y08-052] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In vivo fatty acid synthesis and the pathways of glycerol-3-phosphate (G3P) production were investigated in brown adipose tissue (BAT) from rats fed a cafeteria diet for 3 weeks. In spite of BAT activation, the diet promoted an increase in the carcass fatty acid content. Plasma insulin levels were markedly increased in cafeteria diet-fed rats. Two insulin-sensitive processes, in vivo fatty acid synthesis and in vivo glucose uptake (which was used to evaluate G3P generation via glycolysis) were increased in BAT from rats fed the cafeteria diet. Direct glycerol phosphorylation, evaluated by glycerokinase (GyK) activity and incorporation of [U-14C]glycerol into triacylglycerol (TAG)-glycerol, was also markedly increased in BAT from these rats. In contrast, the cafeteria diet induced a marked reduction of BAT glyceroneogenesis, evaluated by phosphoenolpyruvate carboxykinase-C activity and incorporation of [1-14C]pyruvate into TAG-glycerol. BAT denervation resulted in an approximately 50% reduction of GyK activity, but did not significantly affect BAT in vivo fatty acid synthesis, in vivo glucose uptake, or glyceroneogenesis. The data suggest that the supply of G3P for BAT TAG synthesis can be adjusted independently from the sympathetic nervous system and solely by reciprocal changes in the generation of G3P via glycolysis and via glyceroneogenesis, with no participation of direct phosphorylation of glycerol by GyK.
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Affiliation(s)
- Valéria E Chaves
- Department of Physiology, School of Medicine, University of Sao Paulo, 14049-900 Ribeirao Preto, Sao Paulo, Brazil
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Martins-Santos MES, Chaves VE, Frasson D, Boschini RP, Garófalo MAR, Kettelhut IDC, Migliorini RH. Glyceroneogenesis and the supply of glycerol-3-phosphate for glyceride-glycerol synthesis in liver slices of fasted and diabetic rats. Am J Physiol Endocrinol Metab 2007; 293:E1352-7. [PMID: 17726141 DOI: 10.1152/ajpendo.00394.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pathways of glycerol-3-phosphate (G3P) generation for glyceride synthesis were examined in precision-cut liver slices of fasted and diabetic rats. The incorporation of 5 mM [U-(14)C]glucose into glyceride-glycerol, used to evaluate G3P generation via glycolysis, was reduced by approximately 26-36% in liver slices of fasted and diabetic rats. The glycolytic flux was reduced by approximately 60% in both groups. The incorporation of 1.0 mM [2-(14)C]pyruvate into glyceride-glycerol (glyceroneogenesis) increased approximately 50% and approximately 36% in slices of fasted and diabetic rats, respectively, which also showed a two-fold increase in the activity phosphoenolpyruvate carboxykinase. The increased incorporation of 1.0 mM [2-(14)C]pyruvate into glyceride-glycerol by slices of fasted rats was not affected by the addition of 5 mM glucose to the incubation medium. The activity of glycerokinase and the incorporation of 1 mM [U-(14)C]glycerol into glyceride-glycerol, evaluators of G3P formation by direct glycerol phosphorylation, did not differ significantly from controls in slices of the two experimental groups. Rates of incorporation of 1 mM [2-(14)C]pyruvate and [U-(14)C]glycerol into glucose of incubation medium (gluconeogenesis) were approximately 140 and approximately 20% higher in fasted and diabetic slices than in control slices. It could be estimated that glyceroneogenesis by liver slices of fasted rats contributed with approximately 20% of G3P generated for glyceride-glycerol synthesis, the glycolytic pathway with approximately 5%, and direct phosphorylation of glycerol by glycerokinase with approximately 75%. Pyruvate contributed with 54% and glycerol with 46% of gluconeogenesis. The present data indicate that glyceroneogenesis has a significant participation in the generation of G3P needed for the increased glyceride-glycerol synthesis in liver during fasting and diabetes.
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Meyer LE, Machado LB, Santiago APSA, da-Silva WS, De Felice FG, Holub O, Oliveira MF, Galina A. Mitochondrial Creatine Kinase Activity Prevents Reactive Oxygen Species Generation. J Biol Chem 2006; 281:37361-71. [PMID: 17028195 DOI: 10.1074/jbc.m604123200] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
As recently demonstrated by our group (da-Silva, W. S., Gómez-Puyou, A., Gómez-Puyou, M. T., Moreno-Sanchez, R., De Felice, F. G., de Meis, L., Oliveira, M. F., and Galina, A. (2004) J. Biol. Chem. 279, 39846-39855) mitochondrial hexokinase activity (mt-HK) plays a preventive antioxidant role because of steady-state ADP re-cycling through the inner mitochondrial membrane in rat brain. In the present work we show that ADP re-cycling accomplished by the mitochondrial creatine kinase (mt-CK) regulates reactive oxygen species (ROS) generation, particularly in high glucose concentrations. Activation of mt-CK by creatine (Cr) and ATP or ADP, induced a state 3-like respiration in isolated brain mitochondria and prevention of H(2)O(2) production obeyed the steady-state kinetics of the enzyme to phosphorylate Cr. The extension of the preventive antioxidant role of mt-CK depended on the phosphocreatine (PCr)/Cr ratio. Rat liver mitochondria, which lack mt-CK activity, only reduced state 4-induced H(2)O(2) generation when 1 order of magnitude more exogenous CK activity was added to the medium. Simulation of hyperglycemic conditions, by the inclusion of glucose 6-phosphate in mitochondria performing 2-deoxyglucose phosphorylation via mt-HK, induced H(2)O(2) production in a Cr-sensitive manner. Simulation of hyperglycemia in embryonic rat brain cortical neurons increased both DeltaPsi(m) and ROS production and both parameters were decreased by the previous inclusion of Cr. Taken together, the results presented here indicate that mitochondrial kinase activity performed a key role as a preventive antioxidant against oxidative stress, reducing mitochondrial ROS generation through an ADP-recycling mechanism.
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Affiliation(s)
- Laudiene Evangelista Meyer
- Instituto de Bioquímica Médica, Programa de Biofísica e Bioquímica Celular and Programa de Biologia Molecular e Biotecnologia
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Chaves VE, Frasson D, Martins-Santos MES, Boschini RP, Garófalo MAR, Festuccia WTL, Kettelhut IC, Migliorini RH. Glyceroneogenesis is reduced and glucose uptake is increased in adipose tissue from cafeteria diet-fed rats independently of tissue sympathetic innervation. J Nutr 2006; 136:2475-80. [PMID: 16988112 DOI: 10.1093/jn/136.10.2475] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The pathways of glycerol-3-P (G3P) generation were examined in retroperitoneal (RETRO) and epididymal (EPI) adipose tissues from rats fed a cafeteria diet for 3 wk. The cafeteria diet induced marked increases in body fat mass and in the plasma levels of insulin and triacylglycerol (TAG). RETRO and EPI from cafeteria diet-fed rats had increased rates of norepinephrine turnover (143 and 60%, respectively) and of de novo fatty acid (FA) synthesis (58 and 98%), compared with controls fed a balanced commercial diet. Cafeteria diet feeding induced marked increases in RETRO and EPI in vivo rates of glucose uptake (52 and 51%, respectively), used to evaluate G3P generation via glycolysis, as well as in glycerokinase activity (119 and 36%) and TAG-glycerol synthesis from glycerol (56 and 71%, respectively). In contrast, there was a marked reduction of glyceroneogenesis in RETRO and EPI from cafeteria diet-fed rats, which was evidenced by the significant decreases of P-enolpyruvate carboxykinase (PEPCK-C) activity (48 and 36%) and TAG-glycerol synthesis from pyruvate (45 and 56%, respectively). Denervation of RETRO from cafeteria diet-fed rats reduced the activity of glycerokinase by 50%, but did not affect glucose uptake or PEPCK-C activity and TAG-glycerol synthesis from pyruvate by the tissue. The data show that glyceroneogenesis can also be inhibited to adjust the supply of G3P to the existing rates of FA esterification and TAG synthesis and suggest that this adjustment is made by reciprocal changes in the generation of G3P from glucose via glycolysis and from glyceroneogenesis, independently from G3P production by glycerokinase.
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Affiliation(s)
- Valéria E Chaves
- Department of Physiology, School of Medicine, University of São Paulo, 14049-900 Ribeirão Preto, São Paulo, Brazil
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15
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Leroyer SN, Tordjman J, Chauvet G, Quette J, Chapron C, Forest C, Antoine B. Rosiglitazone Controls Fatty Acid Cycling in Human Adipose Tissue by Means of Glyceroneogenesis and Glycerol Phosphorylation. J Biol Chem 2006; 281:13141-13149. [PMID: 16524879 DOI: 10.1074/jbc.m512943200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Control of fatty acid homeostasis is crucial to prevent insulin resistance. During fasting, the plasma fatty acid level depends on triglyceride lipolysis and fatty acid re-esterification within fat cells. In rodents, Rosiglitazone controls fatty acid homeostasis by stimulating two pathways in the adipocytes, glyceroneogenesis and glycerol phosphorylation, that provide the glycerol 3-phosphate necessary for fatty acid re-esterification. Here, we analyzed the functionality of both pathways for controlling fatty acid release in subcutaneous adipose tissue samples from lean and overweight women before and after Rosiglitazone ex vivo treatment. In controls, pyruvate, used as a substrate of glyceroneogenesis, could contribute to the re-esterification of up to 65% of the fatty acids released after basal lipolysis, whereas glycerol phosphorylation accounted for only 14 +/- 9%. However, the efficiency of glyceroneogenesis diminished as body mass index (BMI) of women increased. After Rosiglitazone treatment, increase of either pyruvate- or glycerol-dependent fatty acid re-esterification was strictly correlated to that of phosphoenolpyruvate carboxykinase and glycerol kinase, the key enzymes of each pathway, but depended on BMI of the women. Whereas the Rosiglitazone responsiveness of glyceroneogenesis was rather constant according to the BMI of the women, glycerol phosphorylation was mostly enhanced in lean women (BMI < 27). Overall, these data indicate that, whereas glyceroneogenesis is more utilized than glycerol phosphorylation for fatty acid re-esterification in human subcutaneous adipose tissue in the physiological situation, both are solicited in response to Rosiglitazone but with lower efficiency when BMI is increased.
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Affiliation(s)
- Stéphanie N Leroyer
- INSERM-UMR-S 530/747, Université Paris Descartes, 45 Rue des Saints-Pères, 75006 Paris, France
| | - Joan Tordjman
- INSERM-UMR-S 530/747, Université Paris Descartes, 45 Rue des Saints-Pères, 75006 Paris, France
| | - Geneviève Chauvet
- INSERM-UMR-S 530/747, Université Paris Descartes, 45 Rue des Saints-Pères, 75006 Paris, France
| | - Joëlle Quette
- INSERM-UMR-S 530/747, Université Paris Descartes, 45 Rue des Saints-Pères, 75006 Paris, France
| | - Charles Chapron
- Groupe Hospitalier Universitaire Ouest, Centre Hospitalier Universitaire Cochin, Paris, France
| | - Claude Forest
- INSERM-UMR-S 530/747, Université Paris Descartes, 45 Rue des Saints-Pères, 75006 Paris, France
| | - Bénédicte Antoine
- INSERM-UMR-S 530/747, Université Paris Descartes, 45 Rue des Saints-Pères, 75006 Paris, France.
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16
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Festuccia WTL, Kawashita NH, Garofalo MAR, Moura MAF, Brito SRC, Kettelhut IC, Migliorini RH. Control of glyceroneogenic activity in rat brown adipose tissue. Am J Physiol Regul Integr Comp Physiol 2003; 285:R177-82. [PMID: 12793997 DOI: 10.1152/ajpregu.00713.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Brown adipose tissue (BAT) glyceroneogenesis was evaluated in rats either fasted for 48 h or with streptozotocin-diabetes induced 3 days previously or adapted for 20 days to a high-protein, carbohydrate-free (HP) diet, conditions in which BAT glucose utilization is reduced. The three treatments induced an increase in BAT glyceroneogenic activity, evidenced by increased rates of incorporation of [1-14C]pyruvate into triacylglycerol (TAG)-glycerol in vitro and a marked, threefold increase in the activity of BAT phosphoenolpyruvate carboxykinase (PEPCK). BAT glycerokinase activity was not significantly affected by fasting or diabetes. After unilateral BAT denervation of rats fed either the HP or a balanced diet, glyceroneogenesis activity increased in denervated pads, evidenced by increased rates of nonglucose carbon incorporation into TAG-glycerol in vivo (difference between 3H2O and [14C]glucose incorporations) and of [1-14C]pyruvate in vitro. PEPCK activity was not significantly affected by denervation. The data suggest that BAT glyceroneogenesis is not under sympathetic control but is sensitive to hormonal/metabolic factors. In situations of reduced glucose use there is an increase in BAT glyceroneogenesis that may compensate the decreased generation of glycerol-3-phosphate from the hexose.
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Affiliation(s)
- W T L Festuccia
- Dept. of Biochemistry and Immunology, School of Medicine, 14049-900 Ribeirão Preto, SP, Brazil
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17
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Kawashita NH, Festuccia WTL, Brito MN, Moura MAF, Brito SRC, Garófalo MAR, Kettelhut IC, Migliorini RH. Glycerokinase activity in brown adipose tissue: a sympathetic regulation? Am J Physiol Regul Integr Comp Physiol 2002; 282:R1185-90. [PMID: 11893624 DOI: 10.1152/ajpregu.00419.2001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of brown adipose tissue (BAT) sympathetic hemidenervation on the activity of glycerokinase (GyK) was investigated in different physiological conditions. In rats fed a balanced diet, the activity of the enzyme was approximately 50% lower in BAT-denervated pads than in intact, innervated pads. In rats adapted to a high-protein, carbohydrate-free diet, norepinephrine turnover rates and BAT GyK activity were already reduced, and BAT denervation resulted in a further decrease in the activity of the enzyme. Cold acclimation of normally fed rats at 4 degrees C for 10 days markedly increased the activity of the enzyme. Cold exposure (4 degrees C) for 6 h was insufficient to stimulate BAT GyK, but the activity of the enzyme was already increased after 12 h of cold exposure. The cold-induced BAT GyK stimulation was completely blocked in BAT-denervated pads. The data indicate that an adequate sympathetic flow to BAT is required for the maintenance of normal levels of GyK activity and for the enzyme response to situations, such as cold exposure, which markedly increase BAT sympathetic flow.
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Affiliation(s)
- N H Kawashita
- Departments of Biochemistry, Immunology and Physiology, School of Medicine, University of São Paulo, Ribeirão Preto, 14049-900 São Paulo, Brazil
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18
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Downie MM, Kealey T. Lipogenesis in the human sebaceous gland: glycogen and glycerophosphate are substrates for the synthesis of sebum lipids. J Invest Dermatol 1998; 111:199-205. [PMID: 9699717 DOI: 10.1046/j.1523-1747.1998.00264.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The lipid class compositions of freshly isolated and overnight maintained human sebaceous glands were determined using high performance thin layer chromatography and were found to be broadly similar. The lipid classes identified in freshly isolated glands were broadly similar to those generated from various radiolabeled precursors in vitro, although lower amounts of wax/sterol esters and cholesterol were observed in vitro. We determined the glycogen content of sebaceous glands and showed that during their incubation with several radiolabeled substrates, with the exception of [U-14C]glucose, significant glycogen breakdown occurred, thus providing acetyl-CoA and NADPH that could affect the pattern of lipids synthesized. We examined glycogen-depleted glands and found that their rates and pattern of lipogenesis resemble that of nondepleted glands, except that the squalene/triacylglycerides ratio for acetate and glutamine doubled from 1.6:1 to 3.4:1 and from 0.7:1 to 1.4:1, respectively. We have shown that exogenous glycerol reduces the squalene/triacylglycerides ratio from acetate from 3.4:1 to 1.7:1, suggesting that glycogen-derived glycerophosphate is important in triacylglycerides synthesis from acetate. Moreover, glands express a glycerokinase activity that may fully account for the rate of triacylglycerides synthesis seen in vitro. We conclude that glycerophosphate generation may be as important as NADPH generation in explaining the directing effects of different substrates within the sebaceous gland.
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Affiliation(s)
- M M Downie
- Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, UK
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19
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Clarke RA, Howard N, O'Sullivan WJ, Svirklys LG, Mackinlay AG. Glycerol kinase deficiency and adrenal hypoplasia congenita. J Inherit Metab Dis 1997; 20:609. [PMID: 9266403 DOI: 10.1023/a:1005327713890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R A Clarke
- School of Biochemistry and Molecular Genetics, University of NSW, Sydney, Australia
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20
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21
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Calder PC, Yaqoob P, Newsholme EA. Triacylglycerol metabolism by lymphocytes and the effect of triacylglycerols on lymphocyte proliferation. Biochem J 1994; 298 Pt 3:605-11. [PMID: 8141773 PMCID: PMC1137902 DOI: 10.1042/bj2980605] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This study investigates the ability of lymphocytes to utilize fatty acids originating from triacylglycerols and the effect of triacylglycerols upon mitogen-stimulated lymphocyte proliferation. Lymphocytes isolated from rat lymph nodes, spleen, thymus and lymphatic duct had a lipoprotein lipase activity of approx. 10 units/mg of protein, indicating that the fatty acids of circulating triacylglycerols are accessible to these cells. In culture lymph node lymphocytes hydrolysed triacylglycerols added to the medium as emulsions. Both non-esterified fatty acids and free glycerol appeared in the cell culture medium, but their concentrations indicated that a high proportion of each (65-90% of fatty acids and 60-80% of glycerol) was taken up by the cells. The incorporation and fate of triacylglycerol-fatty acids was studied by culturing the cells in the presence of tri[3H]oleoylglycerol or tri[14C]inoleoylglycerol. Both fatty acids were incorporated into lymphocyte lipids in a time-dependent manner; linoleic acid was incorporated at a significantly greater rate than oleic acid. The majority of oleic acid (greater than 70%) was incorporated into cellular triacylglycerol, while less than 10% was incorporated into phospholipids. In contrast, linoleic acid incorporation into cellular triacylglycerol never exceeded 25%, while up to 45% was incorporated into phospholipids. Triacylglycerols containing polyunsaturated fatty acids inhibited concanavalin A-stimulated lymphocyte proliferation in a concentration- and time-dependent manner; triacylglycerols containing saturated fatty acids or oleic acid were not inhibitory. Such direct effects of certain triacylglycerols on lymphocyte function may explain why some clinical trials of polyunsaturated fatty acid-rich diets have been successful in improving the condition of patients suffering from inflammatory diseases.
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Affiliation(s)
- P C Calder
- Department of Biochemistry, University of Oxford, UK
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22
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Sakura N, Nishimura S, Kawahara N, Komazawa Y, Yamaguchi S. Asthma as the first presenting symptom of complex glycerol kinase deficiency. ACTA PAEDIATRICA SCANDINAVICA 1991; 80:723-5. [PMID: 1867094 DOI: 10.1111/j.1651-2227.1991.tb11936.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Two patients presenting with asthma as the first clinical symptom of a mild form of Addison crisis were found to have complex glycerol kinase deficiency (CGKD). They had been treated with bronchodilators prior to the exact diagnosis. Asthma may appear in a mild form of Addison crisis in a patient with CGKD. Pediatricians should be aware of this unusual presentation of CGKD.
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Affiliation(s)
- N Sakura
- Department of Pediatrics, Hiroshima University School of Medicine, Japan
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23
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24
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Nilsson A, Thomson KS, Adler L. Purification and characterization of glycerol kinase in the salt-tolerant yeast Debaryomyces hansenii. Biochim Biophys Acta Gen Subj 1989. [DOI: 10.1016/0304-4165(89)90119-0] [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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25
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Seltzer WK, Angelini C, Dhariwal G, Ringel SP, McCabe ER. Muscle glycerol kinase in Duchenne dystrophy and glycerol kinase deficiency. Muscle Nerve 1989; 12:307-13. [PMID: 2549414 DOI: 10.1002/mus.880120409] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The complex glycerol kinase deficiency (GKD) syndrome is an X-linked recessive genetic disorder. The syndrome often includes a myopathy that is similar histologically to Duchenne muscular dystrophy (DMD). The glycerol kinase (GK) locus is in the Xp21 region in the midportion of the short arm of the X chromosome and is in close proximity to the DMD locus. We have investigated GK activity and subcellular distribution of muscle GK in DMD patients and in a patient with the complex GKD syndrome presenting with myopathy. We found no abnormality of muscle GK specific activity or subcellular distribution in DMD. In the patient with the complex GKD syndrome the specific activity and kinetics of muscle GK were normal, but the subcellular distribution of muscle GK was altered. Liver GK had less than 10% of normal activity and showed markedly altered kinetics. These findings indicate that there is no abnormality of muscle GK activity in DMD muscle. Furthermore, the normal GK activity in an individual with the complex GKD syndrome suggests that muscle and liver GK are genetically distinct. These findings support the concept that the complex GKD syndrome results from small deletions that affect closely linked but separate loci for DMD, GK and adrenal hypoplasia.
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Affiliation(s)
- W K Seltzer
- Department of Pediatrics, University of Colorado Health Sciences Center, Denver 80262
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26
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Minter M, Towbin J, Harter J, McCabe ER. Enzyme product blot for nondestructive assay of protein catalytic function in polyacrylamide gels. Anal Biochem 1989; 178:22-6. [PMID: 2729576 DOI: 10.1016/0003-2697(89)90349-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A new method that permits rapid, sensitive, and specific enzymatic assay of proteins in polyacrylamide gels is described. The enzyme product blot described in this report involves percolation of the reaction mixture through a gel containing native enzyme which converts the labeled substrate to a labeled product with differing chemical properties. A permeable membrane with specific ligand-binding properties overlies the gel and binds the enzyme product, but not the substrate, as reaction mixture is blotted vertically. This membrane is washed free of substrate and the location of the product is identified by autoradiography. The autoradiogram is compared with the stained gel in order to recover the enzyme for amino acid sequence analysis. The enzyme product blot is demonstrated using glycerol kinase and hexokinase.
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Affiliation(s)
- M Minter
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
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27
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Kuhn NJ. Insulin action on the lactating-rat mammary gland: intracellular glucose and its phosphorylation. Biochem J 1989; 257:933-4. [PMID: 2649082 PMCID: PMC1135679 DOI: 10.1042/bj2570933] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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28
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Burke BA, Wick MR, King R, Thompson T, Hansen J, Darrae BT, Francke U, Seltzer WK, McCabe ER, Scheithauer BW. Congenital adrenal hypoplasia and selective absence of pituitary luteinizing hormone: a new autosomal recessive syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 1988; 31:75-97. [PMID: 2906226 DOI: 10.1002/ajmg.1320310111] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Congenital hypoplasia of the adrenal glands (CHA) is a rare condition, particularly in the absence of a central nervous system (CNS) anomaly. Two major types of CHA have been described in the setting of an apparently normal CNS and pituitary: a cytomegalic type usually with X-linked recessive inheritance and a miniature adult type that, when hereditary, is an autosomal recessive trait. Glycerol kinase deficiency (GKD) is an X-linked recessive trait, and it may be associated with CHA and adrenal insufficiency, presumably because of deletion of adjacent X-linked loci. We report on three sibling infants, one male and two females, with normal CNS and lethal CHA of the miniature adult type, selective absence of pituitary LH; two of the infants also had glycerol kinase (GK) activity that was decreased but not in the GKD range. Restriction fragment length polymorphism (RFLP) analysis of X chromosome markers located at Xp21-p22 was carried out on the maternal grandfather, both parents, two of three affected infants, and a living normal brother. The results excluded the X-linked type of this disorder associated with GKD in this family. Autosomal recessive inheritance is most likely.
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Affiliation(s)
- B A Burke
- Department of Laboratory Medicine, University of Minnesota, Minneapolis 55455
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29
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Kee Y, Lee YS, Chung CH, Waxman L, Goldberg AL. Improved methods for purification and assay of glycerol kinase from Escherichia coli. JOURNAL OF CHROMATOGRAPHY 1988; 428:345-51. [PMID: 2851011 DOI: 10.1016/s0378-4347(00)83926-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Y Kee
- Department of Zoology, College of Natural Sciences, Seoul National University, Korea
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30
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Abstract
Homogenates of rat pancreatic islets and tumoral islet cells (RINm5F line) were found to display glycerokinase activity. In the islets like in the liver, about one-sixth of the enzyme appears bound to mitochondria. The enzymatic activities in liver and islets differ from one another, however, by their response to increasing concentrations of either glycerol or ATP and sensitivity to inhibition by D-glyceraldehyde. In intact islets, [U-14C]glycerol is efficiently oxidized, albeit at a much lower rate than that found for its phosphorylation by islet homogenates. These findings are relevant to the role played by glycerol liberated from endogenous triglycerides in the basal respiration of islet cells.
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Affiliation(s)
- M T Yilmaz
- Department of Metabolism and Nutrition, Cerrahpasa Faculty of Medicine, Istanbul University, Turkey
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31
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Simpson ML, Cooney GJ, Caterson ID, Newsholme EA. Glycolysis and lipid synthesis in brown adipose tissue during ageing in the rat. Biochem Biophys Res Commun 1986; 140:419-26. [PMID: 3535790 DOI: 10.1016/0006-291x(86)91107-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The maximal activity of the enzymes hexokinase and 6-phosphofructokinase were measured in interscapular brown adipose tissue during ageing in the rat. The activity of these glycolytic enzymes increased markedly during the suckling-weaning transition (20-22 days of age), but from 30 to 100 days of age the activities per gram wet weight and per mg protein decreased. The rate of lipogenesis in brown adipose tissue was also increased over the suckling-weaning transition and the contribution of glucose to this fatty acid synthesis was greater in weaned animals especially under the influence of insulin.
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32
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Hertz R, Bar-Tana J. Reductive repression in Escherichia coli K-12 is mediated by oxygen radicals. Arch Biochem Biophys 1986; 250:54-62. [PMID: 3532957 DOI: 10.1016/0003-9861(86)90701-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cyclic AMP (cAMP) content and the expression of cAMP-dependent phenotypes were positively correlated with respiration capacity in respiration-deficient mutants of Escherichia coli K-12 ("reductive repression," R. Hertz, and J. Bar-Tana, (1982) Arch. Biochem. Biophys. 213, 193-199). Reductive repression in respiration-deficient mutants could not be accounted for by respective changes in either the energy charge of adenine nucleotides or the redox state of pyridine nucleotides but could be ascribed to an increased formation of oxygen radicals under conditions of limited respiration. Scavengers of superoxide radicals eliminated reductive repression in respiration-deficient mutants with a concomitant increase in cAMP content. Such scavengers also effected a partial escape from permanent glucose catabolite repression, thus indicating a possible role played by oxygen radicals in both repression modes.
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33
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KANEKO MUNEKIYO, ISHIBASHI SADAHIKO. Changes during Development in the Activities and Intracellular Locations of Glycerol Kinase and Hexokinase in Rat Brain and Liver. (brain/liver/enzyme localization/glycerol kinase/hexokinase). Dev Growth Differ 1985. [DOI: 10.1111/j.1440-169x.1985.00745.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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Novotná J, Hošťálek Z. Phosphorylation of hexoses inStreptomyces aureofaciens: Evidence that the phosphoenolpyruvate: Sugar phosphotransferase system is not operative. FEMS Microbiol Lett 1985. [DOI: 10.1111/j.1574-6968.1985.tb00818.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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35
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Adler L, Blomberg A, Nilsson A. Glycerol metabolism and osmoregulation in the salt-tolerant yeast Debaryomyces hansenii. J Bacteriol 1985; 162:300-6. [PMID: 3980438 PMCID: PMC218989 DOI: 10.1128/jb.162.1.300-306.1985] [Citation(s) in RCA: 123] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A glycerol-nonutilizing mutant of the salt-tolerant yeast Debaryomyces hansenii was isolated. When subjected to salt stress the mutant produced glycerol, and the internal level of glycerol increased linearly in proportion to increases of external salinity as in the wild-type strain. However, at increased salinity the mutant showed a more pronounced decrease of growth rate and growth yield and lost more glycerol to the surrounding medium than did the wild type. Uptake experiments showed glycerol to be accumulated against a strong concentration gradient, and both strains displayed similar kinetic parameters for the uptake of glycerol. An examination of enzyme activities of the glycerol metabolism revealed that the apparent Km of the sn-glycerol 3-phosphate dehydrogenase (EC 1.1.99.5) was increased 330-fold for sn-glycerol 3-phosphate in the mutant. Based on the findings, a scheme for the pathways of glycerol metabolism is suggested.
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36
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Kaneko M, Kurokawa M, Ishibashi S. Binding and function of mitochondrial glycerol kinase in comparison with those of mitochondrial hexokinase. Arch Biochem Biophys 1985; 237:135-41. [PMID: 2982325 DOI: 10.1016/0003-9861(85)90262-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mitochondrial-bound glycerol kinase in rat brain was examined with reference to factors involved in the binding and significance of the binding in relation to ATP metabolism inside the mitochondria. The mitochondrial-bound glycerol kinase was solubilized with glycerol 3-phosphate or ADP, and the solubilized enzyme was rebound to mitochondria by addition of divalent cations. The rebinding was decreased by the presence of glycerol 3-phosphate, while was increased by glucose 6-phosphate. Positive correlation was found between the formation of glycerol 3-phosphate by mitochondrial-bound glycerol kinase and ATP content in mitochondria in experiments using various concentrations of succinate and ADP. On the other hand, glycerol 3-phosphate formation was inhibited by addition of inhibitors for mitochondria functions, such as oligomycin, dinitrophenol, cyanide, and atractyloside. Furthermore, formation of dihydroxyacetone phosphate from glycerol was proved, indicating the involvement of glycerol kinase in glycerol phosphate shuttle in combination with glycerol phosphate dehydrogenase. These findings are discussed in comparison with those of mitochondrial-bound hexokinase.
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37
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Seltzer WK, McCabe ER. Subcellular distribution and kinetic properties of soluble and particulate-associated bovine adrenal glycerol kinase. Mol Cell Biochem 1984; 64:51-61. [PMID: 6092910 DOI: 10.1007/bf00420928] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The subcellular distribution and substrate kinetics of soluble and particulate-associated bovine adrenal glycerol kinase have been investigated. Whole adrenal, adrenal cortex and adrenal medulla were examined for distribution of glycerol kinase between soluble and particulate fractions. No major differences in distribution were noted between these tissues; of the total homogenate activity, 0-20% sedimented with the nuclear fraction, 24-36% sedimented with the post-nuclear fraction and 64-69% remained soluble. Steady-state kinetic parameters of glycerol kinase activity were compared in the soluble and mitochondrial fractions. The Km for glycerol in the soluble fraction was 6.3 +/- 0.1 microM and in the mitochondrial fraction was 4.0 +/- 0.3 microM. The Km for ATP in soluble fraction was 12.8 +/- 1.5 and in the mitochondrial fraction was 5.3 +/- 1.6. Release of adrenal glycerol kinase from the mitochondrial fraction was investigated using inorganic phosphate, ATP and glycerol 3-phosphate. Of these compounds, only ATP and glycerol 3-phosphate were effective in releasing particulate-associated glycerol kinase. Inorganic phosphate had no effect upon release. Particulate-associated glycerol kinase activity of the mitochondrial fraction was stimulated by addition of succinate and ADP and was inhibited by addition of atractyloside. The data presented here indicate that bound glycerol kinase found within the mitochondrial fraction is kinetically distinct from soluble glycerol kinase and binding to mitochondria is responsive to substrate and product levels within the physiological range.
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Iida A, Harayama S, Iino T, Hazelbauer GL. Molecular cloning and characterization of genes required for ribose transport and utilization in Escherichia coli K-12. J Bacteriol 1984; 158:674-82. [PMID: 6327617 PMCID: PMC215482 DOI: 10.1128/jb.158.2.674-682.1984] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We isolated spontaneous and transposon insertion mutants of Escherichia coli K-12 that were specifically defective in utilization or in high-affinity transport of D-ribose (or in both). Cotransduction studies located all of the mutations near ilv, at the same position as previously identified mutations causing defects in ribokinase ( rbsK ) or ribose transport ( rbsP ). Plasmids that complemented the rbs mutations were isolated from the collection of ColE1 hybrid plasmids constructed by Clarke and Carbon. Analysis of those plasmids as well as of fragments cloned into pBR322 and pACYC184 allowed definition of the rbs region. Products of rbs genes were identified by examination of the proteins produced in minicells containing various rbs plasmids. We identified four rbs genes: rbsB , which codes for the 29-kilodalton ribose-binding protein; rbsK , which codes for the 34-kilodalton ribokinase ; rbsA , which codes for a 50-kilodalton protein required for high-affinity transport; and rbsC , which codes for a 27-kilodalton protein likely to be a transport system component. Our studies showed that these genes are transcribed from a common promoter in the order rbsA rbsC rbsB rbsK . It appears that the high-affinity transport system for ribose consists of the three components, ribose-binding protein, the 50-kilodalton RbsA protein, and the 27-kilodalton RbsC protein, although a fourth, unidentified component could exist. Mutants defective in this transport system, but normal for ribokinase , are able to grow normally on high concentrations of the sugar, indicating that there is at least a second, low-affinity transport system for ribose in E. coli K-12.
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Chakrabarty K, Chaudhuri B, Jeffay H. Glycerokinase activity in human brown adipose tissue. J Lipid Res 1983. [DOI: 10.1016/s0022-2275(20)37978-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Pyle JE, Howe HB. Uptake and dissimilation of glycerol by wild type and glycerol nonutilizing strains of Neurospora crassa. MOLECULAR & GENERAL GENETICS : MGG 1983; 189:166-8. [PMID: 6222238 DOI: 10.1007/bf00326071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Seven mutant strains defective for utilization of glycerol, glyceraldehyde or dihydroxyacetone were isolated. One strain was deficient for NAD-linked glycerol-3-phosphate dehydrogenase, two for glycerol kinase, and four had no detected enzymatic deficiency, although one of the latter strains was deficient in glycerol uptake. Glycerol uptake was increased by incubation in glycerol, glycerol-3-phosphate, erythritol, and propanediol, and was protein-mediated below 0.14 mM glycerol, but at higher concentrations free diffusion predominated. Glycerol uptake was decreased by cycloheximide and was more sensitive to sodium azide than to iodoacetate.
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Cooney GJ, Newsholme EA. The maximum capacity of glycolysis in brown adipose tissue and its relationship to control of the blood glucose concentration. FEBS Lett 1982; 148:198-200. [PMID: 6217986 DOI: 10.1016/0014-5793(82)80807-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The maximum activity of the key glycolytic enzymes, hexokinase and 6-phosphofructokinase, was measured in tissues of control and cold-acclimated rats. The only significant change in activity was seen in brown adipose tissue where the activity of these enzymes was increased 2-fold. This increase in glycolytic capacity along with the hypertrophy of BAT observed in cold acclimation suggests that this tissue could play an important role in glucose utilisation by the rat.
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Threadgold LC, Coore HG, Kuhn NJ. Monosaccharide transport into lactating-rat mammary acini. Biochem J 1982; 204:493-501. [PMID: 6214256 PMCID: PMC1158377 DOI: 10.1042/bj2040493] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The uptake and release of 3-O-methyl-D-[3H]glucose at 37 degrees C by acini, prepared from lactating-rat mammary gland with collagenase, was inhibited by glucose, phloretin, cytochalasin B, HgCl2 and low temperature. Uptake and phosphorylation of 2-deoxy-D-[3H]glucose, studied in greater detail, could be ascribed to a specific, saturable, inhibitable, process of apparent Km 16 mM and Vmax. approx. 56 nmol/min per mg of protein, plus a non-specific, non-inhibitable process that was monitored with [14C]fructose. The mean rate of uptake of 5 mM-2-deoxyglucose (16 nmol/min per mg of protein) was similar to the rate of consumption of 5 mM-glucose, suggesting that transport was a rate-limiting step in the overall metabolism of glucose. This accords with evidence for a glucose gradient across the plasma membrane.
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McCabe ER, Sadava D, Bullen WW, McKelvey HA, Seltzer WK, Rose CI. Human glycerol kinase deficiency: enzyme kinetics and fibroblast hybridization. J Inherit Metab Dis 1982; 5:177-82. [PMID: 6302392 DOI: 10.1007/bf02179133] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glycerol kinase deficiency has been associated with neuromuscular, skeletal and adrenal abnormalities and has also been seen in individuals without these clinical findings. Examination of residual enzyme activity in patients' liver, kidney, leukocytes and fibroblasts showed a generalized, heritable defect: the apparent Km for glycerol was increased 5-200-fold over control values, whereas the apparent Km for ATP was not significantly altered. This kinetic defect was similar in fibroblasts from clinically different individuals with this inborn error of metabolism. Hybridization of fibroblasts from these individuals showed no evidence of complementation for glycerol kinase activity.
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Wirthensohn G, Vandewalle A, Guder WG. Renal glycerol metabolism and the distribution of glycerol kinase in rabbit nephron. Biochem J 1981; 198:543-9. [PMID: 6275852 PMCID: PMC1163300 DOI: 10.1042/bj1980543] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glycerol and dihydroxyacetone are metabolized by rabbit kidney-cortex tubules, isolated by collagenase treatment. Half-maximal concentrations of both substrates were determined with regard to uptake rates and product formations. Maximal uptake rates were 643 and 329 mumol/h per g of protein for dihydroxyacetone and glycerol respectively. Glucose and lactate were found as major metabolic products. Glycerol kinase, the enzyme catalysing the first step in renal glycerol and dihydroxyacetone metabolism, was measured radiochemically as described by Newsholme, Robinson & Taylor [(1967) Biochim, Biophys. Acta 132, 338-346] and adapted for studies of the localization of this enzyme along the different structures of rabbit nephron. The results show that glycerol kinase is located exclusively in the proximal segments, i.e. the proximal convoluted tubules and the pars recta, but is negligible in the other structures studied. The activities were close to the maximal dihydroxyacetone uptake rates measured in tubule suspensions.
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Crabtree B, Taylor DJ, Coombs JE, Smith RA, Templer SP, Smith GH. The activities and intracellular distributions of enzymes of carbohydrate, lipid and ketone-body metabolism in lactating mammary glands from ruminants and non-ruminants. Biochem J 1981; 196:747-56. [PMID: 7317013 PMCID: PMC1163094 DOI: 10.1042/bj1960747] [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: 01/24/2023]
Abstract
1. The activities of several enzymes of carbohydrate, lipid, acetate and ketone-body metabolism were measured in lactating mammary glands from rats, mice, rabbits, guinea pigs, sows, sheep, cows and goats. The intracellular distributions of many of the enzymes were measured by fractional extraction. 2. Acetyl-CoA synthetase was predominantly cytoplasmic in rats and guinea pigs, but was more mitochondrial in the other species. The different location of this enzyme in rats and mice is discussed in relation to the disposal of reducing equivalents. 3. 3-Oxo acid CoA-transferase and acetoacetyl-CoA thiolase assayed at 600 microM-CoA were predominantly mitochondrial in all species investigated. Acetoacetyl-CoA thiolase assayed at 8 microM-CoA was predominantly cytoplasmic, except in rabbits and guinea pigs. Ruminants appeared to possess little, if any, of the cytoplasmic enzyme. 4. The activities and distributions of NADP-isocitrate dehydrogenase were consistent with a role in supplying cytoplasmic NADPH in ruminant tissue, and indicated that this system may also occur in guinea pigs.
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Newton RS, Freedland RA. The effects of specific lipogenic substrates and metabolic inhibitors on de novo fatty acid synthesis in isolated hepatocytes from chow-fed female rats. Arch Biochem Biophys 1980; 204:379-86. [PMID: 7425643 DOI: 10.1016/0003-9861(80)90046-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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47
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Barrera LA, Ho R. Adipose glycerol kinase: low molecular weight protein has two Michaelis constants for glycerol. Biochem Biophys Res Commun 1979; 86:145-52. [PMID: 35161 DOI: 10.1016/0006-291x(79)90393-0] [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: 12/12/2022]
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Deus B, Blum HE. Assay of thiamine pyrophosphokinase (ATP: thiamine pyrophosphotransferase, EC 2.7.6.2) using anion-exchange paper disks. Methods Enzymol 1979; 62:103-4. [PMID: 220501 DOI: 10.1016/0076-6879(79)62200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Gluconeogenesis by isolated hepatocytes resulted in glucose release but insignificant rates of glycogen synthesis. The effectiveness of precursors was similar for hepatocytes from fed and starved chickens except for impaired gluconeogenesis from pyruvate when compared to lactate in lactate starved chicken hepatocytes. The impairment was caused by limitations in cytosolic NADH production as a result of the mitochondrial location of phosphoenolpyruvate carboxykinase in chicken liver. The order of effectiveness of precursors on hepatic gluconeogenesis was generally similar to the effects of precursors on increasing the plasma glucose concentration in vivo. The exceptions were caused by interactions with other precursors in vivo. The alteration of the NADH/NAD+ ratio by ethanol and ATP/ADP ratio by adenosine could play significant roles in the control of precursor conversion to glucose. Physiological glucagon concentrations stimulated gluconeogenesis from precursors entering the pathway both above and below the level of triose phosphates, and its effect were mimicked by dibutyryl cyclic AMP. Previous results on the effects of precursor and glucagon injection on the plasma glucose concentration of chickens in vivo can largely be explained by effects at the hepatic level. Isolated chicken and rat hepatocytes share many common features. Qualitatively the ordering of gluconeogenic effectiveness was similar but quantitive differences existed as a result of differing activities and cellular locations of enzymes. Neither preparation readily synthesised glycogen and the sensitivity to glucagon was similar.
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Leech AR, Beis I, Newsholme EA. Radiochemical assays for creatine kinase and arginine kinase using rapid ion exchange separations. Anal Biochem 1978; 90:561-75. [PMID: 215057 DOI: 10.1016/0003-2697(78)90150-1] [Citation(s) in RCA: 11] [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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