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Edwards MM, Nguyen HK, Dodson AD, Herbertson AJ, Wolden-Hanson T, Wietecha TA, Honeycutt MK, Slattery JD, O’Brien KD, Graham JL, Havel PJ, Mundinger TO, Sikkema CL, Peskind ER, Ryu V, Taborsky GJ, Blevins JE. Sympathetic innervation of interscapular brown adipose tissue is not a predominant mediator of oxytocin-elicited reductions of body weight and adiposity in male diet-induced obese mice. Front Endocrinol (Lausanne) 2024; 15:1440070. [PMID: 39145314 PMCID: PMC11321955 DOI: 10.3389/fendo.2024.1440070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 06/28/2024] [Indexed: 08/16/2024] Open
Abstract
Previous studies indicate that CNS administration of oxytocin (OT) reduces body weight in high fat diet-induced obese (DIO) rodents by reducing food intake and increasing energy expenditure (EE). We recently demonstrated that hindbrain (fourth ventricular [4V]) administration of OT elicits weight loss and elevates interscapular brown adipose tissue temperature (TIBAT, a surrogate measure of increased EE) in DIO mice. What remains unclear is whether OT-elicited weight loss requires increased sympathetic nervous system (SNS) outflow to IBAT. We hypothesized that OT-induced stimulation of SNS outflow to IBAT contributes to its ability to activate BAT and elicit weight loss in DIO mice. To test this hypothesis, we determined the effect of disrupting SNS activation of IBAT on the ability of 4V OT administration to increase TIBAT and elicit weight loss in DIO mice. We first determined whether bilateral surgical SNS denervation to IBAT was successful as noted by ≥ 60% reduction in IBAT norepinephrine (NE) content in DIO mice. NE content was selectively reduced in IBAT at 1-, 6- and 7-weeks post-denervation by 95.9 ± 2.0, 77.4 ± 12.7 and 93.6 ± 4.6% (P<0.05), respectively and was unchanged in inguinal white adipose tissue, pancreas or liver. We subsequently measured the effects of acute 4V OT (1, 5 µg ≈ 0.99, 4.96 nmol) on TIBAT in DIO mice following sham or bilateral surgical SNS denervation to IBAT. We found that the high dose of 4V OT (5 µg ≈ 4.96 nmol) elevated TIBAT similarly in sham mice as in denervated mice. We subsequently measured the effects of chronic 4V OT (16 nmol/day over 29 days) or vehicle infusions on body weight, adiposity and food intake in DIO mice following sham or bilateral surgical denervation of IBAT. Chronic 4V OT reduced body weight by 5.7 ± 2.23% and 6.6 ± 1.4% in sham and denervated mice (P<0.05), respectively, and this effect was similar between groups (P=NS). OT produced corresponding reductions in whole body fat mass (P<0.05). Together, these findings support the hypothesis that sympathetic innervation of IBAT is not necessary for OT-elicited increases in BAT thermogenesis and reductions of body weight and adiposity in male DIO mice.
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Affiliation(s)
- Melise M. Edwards
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Ha K. Nguyen
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Andrew D. Dodson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Adam J. Herbertson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Tami Wolden-Hanson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Tomasz A. Wietecha
- Division of Cardiology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
- UW Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, WA, United States
| | - Mackenzie K. Honeycutt
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Jared D. Slattery
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Kevin D. O’Brien
- Division of Cardiology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
- UW Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, WA, United States
| | - James L. Graham
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Peter J. Havel
- Department of Nutrition, University of California, Davis, Davis, CA, United States
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Thomas O. Mundinger
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
| | - Carl L. Sikkema
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States
| | - Elaine R. Peskind
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States
| | - Vitaly Ryu
- Department of Medicine and Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Gerald J. Taborsky
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
| | - James E. Blevins
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
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2
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Edwards MM, Nguyen HK, Dodson AD, Herbertson AJ, Wolden-Hanson T, Wietecha T, Honeycutt MK, Slattery JD, O'Brien KD, Graham JL, Havel PJ, Mundinger TO, Sikkema C, Peskind ER, Ryu V, Taborsky GJ, Blevins JE. Sympathetic innervation of interscapular brown adipose tissue is not a predominant mediator of oxytocin-elicited reductions of body weight and adiposity in male diet-induced obese mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.596425. [PMID: 38854021 PMCID: PMC11160755 DOI: 10.1101/2024.05.29.596425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Previous studies indicate that CNS administration of oxytocin (OT) reduces body weight in high fat diet-induced obese (DIO) rodents by reducing food intake and increasing energy expenditure (EE). We recently demonstrated that hindbrain (fourth ventricular [4V]) administration of OT elicits weight loss and elevates interscapular brown adipose tissue temperature (T IBAT , a surrogate measure of increased EE) in DIO mice. What remains unclear is whether OT-elicited weight loss requires increased sympathetic nervous system (SNS) outflow to IBAT. We hypothesized that OT-induced stimulation of SNS outflow to IBAT contributes to its ability to activate BAT and elicit weight loss in DIO mice. To test this hypothesis, we determined the effect of disrupting SNS activation of IBAT on the ability of 4V OT administration to increase T IBAT and elicit weight loss in DIO mice. We first determined whether bilateral surgical SNS denervation to IBAT was successful as noted by ≥ 60% reduction in IBAT norepinephrine (NE) content in DIO mice. NE content was selectively reduced in IBAT at 1-, 6- and 7-weeks post-denervation by 95.9±2.0, 77.4±12.7 and 93.6±4.6% ( P <0.05), respectively and was unchanged in inguinal white adipose tissue, pancreas or liver. We subsequently measured the effects of acute 4V OT (1, 5 µg ≈ 0.99, 4.96 nmol) on T IBAT in DIO mice following sham or bilateral surgical SNS denervation to IBAT. We found that the high dose of 4V OT (5 µg ≈ 4.96 nmol) elevated T IBAT similarly in sham mice as in denervated mice. We subsequently measured the effects of chronic 4V OT (16 nmol/day over 29 days) or vehicle infusions on body weight, adiposity and food intake in DIO mice following sham or bilateral surgical denervation of IBAT. Chronic 4V OT reduced body weight by 5.7±2.23% and 6.6±1.4% in sham and denervated mice ( P <0.05), respectively, and this effect was similar between groups ( P =NS). OT produced corresponding reductions in whole body fat mass ( P <0.05). Together, these findings support the hypothesis that sympathetic innervation of IBAT is not necessary for OT-elicited increases in BAT thermogenesis and reductions of body weight and adiposity in male DIO mice.
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3
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Nicholls DG. Mitochondrial proton leaks and uncoupling proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148428. [PMID: 33798544 DOI: 10.1016/j.bbabio.2021.148428] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/15/2021] [Accepted: 03/25/2021] [Indexed: 01/02/2023]
Abstract
Non-shivering thermogenesis in brown adipose tissue is mediated by uncoupling protein 1 (UCP1), which provides a carefully regulated proton re-entry pathway across the mitochondrial inner membrane operating in parallel to the ATP synthase and allowing respiration, and hence thermogenesis, to be released from the constraints of respiratory control. In the 40 years since UCP1 was first described, an extensive, and frequently contradictory, literature has accumulated, focused on the acute physiological regulation of the protein by fatty acids, purine nucleotides and possible additional factors. The purpose of this review is to examine, in detail, the experimental evidence underlying these proposed mechanisms. Emphasis will be placed on the methodologies employed and their relation to the physiological constraints under which the protein functions in the intact cell. The nature of the endogenous, UCP1-independent, proton leak will also be discussed. Finally, the troubled history of the putative novel uncoupling proteins, UCP2 and UCP3, will be evaluated.
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Kannabiran SA, Gosejacob D, Niemann B, Nikolaev VO, Pfeifer A. Real-time monitoring of cAMP in brown adipocytes reveals differential compartmentation of β 1 and β 3-adrenoceptor signalling. Mol Metab 2020; 37:100986. [PMID: 32247064 PMCID: PMC7191645 DOI: 10.1016/j.molmet.2020.100986] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 11/17/2022] Open
Abstract
Objective 3′,5′-Cyclic adenosine monophosphate (cAMP) is a central second messenger governing brown adipocyte differentiation and function. β-adrenergic receptors (β-ARs) stimulate adenylate cyclases which produce cAMP. Moreover, cyclic nucleotide levels are tightly controlled by phosphodiesterases (PDEs), which can generate subcellular microdomains of cAMP. Since the spatio-temporal organisation of the cAMP signalling pathway in adipocytes is still unclear, we sought to monitor real-time cAMP dynamics by live cell imaging in pre-mature and mature brown adipocytes. Methods We measured the real-time dynamics of cAMP in murine pre-mature and mature brown adipocytes during stimulation of individual β-AR subtypes, as well as its regulation by PDEs using a Förster Resonance Energy Transfer based biosensor and pharmacological tools. We also correlated these data with β-AR stimulated lipolysis and analysed the expression of β-ARs and PDEs in brown adipocytes using qPCR and immunoblotting. Furthermore, subcellular distribution of PDEs was studied using cell fractionation and immunoblots. Results Using pre-mature and mature brown adipocytes isolated from transgenic mice expressing a highly sensitive cytosolic biosensor Epac1-camps, we established real-time measurements of cAMP responses. PDE4 turned out to be the major PDE regulating cytosolic cAMP in brown preadipocytes. Upon maturation, PDE3 gets upregulated and contributes with PDE4 to control β1-AR-induced cAMP. Unexpectedly, β3-AR initiated cAMP is resistant to increased PDE3 protein levels and simultaneously, the control of this microdomain by PDE4 is reduced upon brown adipocyte maturation. Therefore we postulate the existence of distinct cAMP pools in brown adipocytes. One cAMP pool is formed by β1-AR associated with PDE3 and PDE4, while another pool is centred around β3-AR and is much less controlled by these PDEs. Functionally, lower control of β3-AR initiated cAMP by PDE3 and PDE4 facilitates brown adipocyte lipolysis, while lipolysis activated by β1-AR and is under tight control of PDE3 and PDE4. Conclusions We have established a real-time live cell imaging approach to analyse brown adipocyte cAMP dynamics in real-time using a cAMP biosensor. We showed that during the differentiation from pre-mature to mature murine brown adipocytes, there was a change in PDE-dependent compartmentation of β1-and β3-AR-initiated cAMP responses by PDE3 and PDE4 regulating lipolysis. Establishment of real-time cAMP analysis using a FRET biosensor in brown adipocytes. Real-time dynamics of cAMP generation from different β-adrenoceptor subtypes in pre- and mature brown adipocytes. Expression analysis of PDE families in pre- and mature brown adipocytes. Differences in PDE3- and PDE4-dependent regulation of β1- and β3-adrenoceptor initiated cAMP signalling in brown adipocytes. Differential compartmentation of β1- and β3-adrenoceptor signalling in brown adipocytes.
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Affiliation(s)
- Sukanya Arcot Kannabiran
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany; Research Training Group 1873, University of Bonn, 53127, Bonn, Germany
| | - Dominic Gosejacob
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany.
| | - Birte Niemann
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany; Bonn International Graduate School of Drug Sciences (BIGS DrugS), Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany.
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany; Research Training Group 1873, University of Bonn, 53127, Bonn, Germany; Bonn International Graduate School of Drug Sciences (BIGS DrugS), Germany.
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5
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Li Y, Fromme T, Klingenspor M. Meaningful respirometric measurements of UCP1-mediated thermogenesis. Biochimie 2016; 134:56-61. [PMID: 27986537 DOI: 10.1016/j.biochi.2016.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/09/2016] [Indexed: 12/22/2022]
Abstract
Regarding the enormous interest in brown and brite/beige adipose tissue in the context of metabolic disease, reliable quantification of thermogenesis in these adipocytes is a central issue. This requires an assay specific for uncoupling protein 1 (UCP1) mediated thermogenesis in adherent intact cells. In a recent study we identified a major pitfall associated with established procedures generally applied for this purpose. Meaningful respirometry of UCP1-mediated thermogenesis imperatively requires activation of UCP1 and control over free fatty acid levels. By comparison of respiration profiles of wild-type (WT) and UCP1 knock-out (KO) cells we reproducibly quantified the thermogenic capacity enabled by UCP1 in both brown and brite adipocytes. Employing this protocol, we demonstrated that (1) brite adipocytes display a similar thermogenic capacity as classical brown adipocytes, (2) variations in brite adipogenesis known for inbred mouse strains are associated with differential capacities for thermogenesis in these cells, and (3) adipose triglyceride lipase (ATGL) activity is required for UCP1 activation in intact cells. We here further refined our cell-based respirometry assay by implementation of two strategies to inhibit UCP1 in WT cells. First, we employed the purine nucleotide guanosine diphosphate (GDP) to directly quantify the fraction of thermogenesis enabled by UCP1 activity. Second, applying siRNA mediated knockdown of UCP1 and ATGL we demonstrated the feasibility of this technology to study the functional relevance of candidate genes for thermogenesis in brown and brite adipocytes.
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Affiliation(s)
- Yongguo Li
- Chair of Molecular Nutritional Medicine, Technical University Munich, Else Kröner-Fresenius Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Tobias Fromme
- Chair of Molecular Nutritional Medicine, Technical University Munich, Else Kröner-Fresenius Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Martin Klingenspor
- Chair of Molecular Nutritional Medicine, Technical University Munich, Else Kröner-Fresenius Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354 Freising, Germany.
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6
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Abstract
The role of mitochondria in white adipocytes has long been neglected due in part to their lower abundance in these cells. However, accumulating evidence suggests that mitochondria are vital for maintaining metabolic homeostasis in white adipocytes because of their involvement in adipogenesis, fatty acid synthesis and esterification, branched-chain amino acid catabolism and lipolysis. It is therefore not surprising that white adipose tissue function can be perturbed by altering mitochondrial components or oxidative capacity. Moreover, studies in humans and animals with significantly altered fat mass, such as in obesity or lipoatrophy, indicate that impaired mitochondrial function in adipocytes may be linked directly to the development of metabolic diseases such as diabetes and insulin resistance. However, recent studies that specifically targeted mitochondrial function in adipocytes indicated dissociation between impaired mitochondrial oxidative capacity and systemic insulin sensitivity.
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Affiliation(s)
- Sihem Boudina
- Division of Endocrinology, Metabolism and Diabetes and Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Timothy E Graham
- Division of Endocrinology, Metabolism and Diabetes and Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
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7
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Seale P, Kajimura S, Yang W, Chin S, Rohas L, Uldry M, Tavernier G, Langin D, Spiegelman BM. Transcriptional control of brown fat determination by PRDM16. Cell Metab 2007; 6:38-54. [PMID: 17618855 PMCID: PMC2564846 DOI: 10.1016/j.cmet.2007.06.001] [Citation(s) in RCA: 890] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 05/03/2007] [Accepted: 06/11/2007] [Indexed: 01/15/2023]
Abstract
Brown fat cells are specialized to dissipate energy and can counteract obesity; however, the transcriptional basis of their determination is largely unknown. We show here that the zinc-finger protein PRDM16 is highly enriched in brown fat cells compared to white fat cells. When expressed in white fat cell progenitors, PRDM16 activates a robust brown fat phenotype including induction of PGC-1alpha, UCP1, and type 2 deiodinase (Dio2) expression and a remarkable increase in uncoupled respiration. Transgenic expression of PRDM16 at physiological levels in white fat depots stimulates the formation of brown fat cells. Depletion of PRDM16 through shRNA expression in brown fat cells causes a near total loss of the brown characteristics. PRDM16 activates brown fat cell identity at least in part by simultaneously activating PGC-1alpha and PGC-1beta through direct protein binding. These data indicate that PRDM16 can control the determination of brown fat fate.
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MESH Headings
- 3T3-L1 Cells
- Adipocytes
- Adipocytes, Brown/metabolism
- Adipocytes, White/metabolism
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, White/metabolism
- Animals
- Blotting, Western
- COS Cells
- Cell Differentiation
- Cell Respiration
- Cells, Cultured
- Chlorocebus aethiops
- DNA-Binding Proteins/physiology
- Electrophoretic Mobility Shift Assay
- Fibroblasts
- Gene Expression Regulation
- Genes, Reporter
- Iodide Peroxidase/genetics
- Iodide Peroxidase/metabolism
- Ion Channels/genetics
- Ion Channels/metabolism
- Male
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Mitochondria
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Oxygen Consumption
- Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
- Phenotype
- Reverse Transcriptase Polymerase Chain Reaction
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription Factors/genetics
- Transcription Factors/physiology
- Transcription, Genetic
- Uncoupling Protein 1
- Iodothyronine Deiodinase Type II
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Affiliation(s)
- Patrick Seale
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
| | - Shingo Kajimura
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
| | - Wenli Yang
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
| | - Sherry Chin
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
| | - Lindsay Rohas
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
| | - Marc Uldry
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
| | - Geneviève Tavernier
- Inserm, U858, Rangueil Institute of Molecular Medicine, Obesity Research Laboratory, Toulouse, F-31432 France
- Paul Sabatier University, Louis Bugnard Institute, IFR31, Toulouse, F-31432 France
| | - Dominique Langin
- Inserm, U858, Rangueil Institute of Molecular Medicine, Obesity Research Laboratory, Toulouse, F-31432 France
- Paul Sabatier University, Louis Bugnard Institute, IFR31, Toulouse, F-31432 France
- CHU de Toulouse, Laboratory of Clinical Biochemistry, Biology Institute of Purpan, Toulouse, F-31059 France
| | - Bruce M. Spiegelman
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School 1 Jimmy Fund Way, Boston, MA 02115
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8
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9
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Shabalina IG, Jacobsson A, Cannon B, Nedergaard J. Native UCP1 displays simple competitive kinetics between the regulators purine nucleotides and fatty acids. J Biol Chem 2004; 279:38236-48. [PMID: 15208325 DOI: 10.1074/jbc.m402375200] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Elucidation of the regulation of uncoupling protein 1 (UCP1) activity in its native environment, i.e. the inner membrane of brown-fat mitochondria, has been hampered by the presence of UCP1-independent, quantitatively unresolved effects of investigated regulators on the brown-fat mitochondria themselves. Here we have utilized the availability of UCP1-ablated mice to dissect UCP1-dependent and UCP1-independent effects of regulators. Using a complex-I-linked substrate (pyruvate), we found that UCP1 can mediate a 4-fold increase in thermogenesis when stimulated with the classical positive regulator fatty acids (oleate). After demonstrating that the fatty acids act in their free form, we found that UCP1 increased fatty acid sensitivity approximately 30-fold (as compared with the 1.5-fold increase reported earlier based on nominal fatty acid values). By identifying the UCP1-mediated fraction of the response, we could conclude that the interaction between purine nucleotides (GDP) and fatty acids (oleate) unexpectedly displayed simple competitive kinetics. In GDP-inhibited mitochondria, oleate apparently acted as an activator. However, only a model in which UCP1 is inherently active (i.e."activating" fatty acids cannot be included in the model), where GDP functions as an inhibitor with a K(m) of 0.05 mm, and where oleate functions as a competitive antagonist for the GDP effect (with a K(i) of 5 nm) can fit all of the experimental data. We conclude that, when examined in its native environment, UCP1 functions as a proton (equivalent) carrier in the absence of exogenous or endogenous fatty acids.
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Affiliation(s)
- Irina G Shabalina
- Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
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10
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Abstract
The function of brown adipose tissue is to transfer energy from food into heat; physiologically, both the heat produced and the resulting decrease in metabolic efficiency can be of significance. Both the acute activity of the tissue, i.e., the heat production, and the recruitment process in the tissue (that results in a higher thermogenic capacity) are under the control of norepinephrine released from sympathetic nerves. In thermoregulatory thermogenesis, brown adipose tissue is essential for classical nonshivering thermogenesis (this phenomenon does not exist in the absence of functional brown adipose tissue), as well as for the cold acclimation-recruited norepinephrine-induced thermogenesis. Heat production from brown adipose tissue is activated whenever the organism is in need of extra heat, e.g., postnatally, during entry into a febrile state, and during arousal from hibernation, and the rate of thermogenesis is centrally controlled via a pathway initiated in the hypothalamus. Feeding as such also results in activation of brown adipose tissue; a series of diets, apparently all characterized by being low in protein, result in a leptin-dependent recruitment of the tissue; this metaboloregulatory thermogenesis is also under hypothalamic control. When the tissue is active, high amounts of lipids and glucose are combusted in the tissue. The development of brown adipose tissue with its characteristic protein, uncoupling protein-1 (UCP1), was probably determinative for the evolutionary success of mammals, as its thermogenesis enhances neonatal survival and allows for active life even in cold surroundings.
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Affiliation(s)
- Barbara Cannon
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
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11
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Nedergaard J, Golozoubova V, Matthias A, Asadi A, Jacobsson A, Cannon B. UCP1: the only protein able to mediate adaptive non-shivering thermogenesis and metabolic inefficiency. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1504:82-106. [PMID: 11239487 DOI: 10.1016/s0005-2728(00)00247-4] [Citation(s) in RCA: 444] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The uniqueness of UCP1 (as compared to UCP2/UCP3) is evident from expression analysis and ablation studies. UCP1 expression is positively correlated with metabolic inefficiency, being increased by cold acclimation (in adults or perinatally) and overfeeding, and reduced in fasting and genetic obesity. Such a simple relationship is not observable for UCP2/UCP3. Studies with UCP1-ablated animals substantiate the unique role of UCP1: the phenomenon of adaptive adrenergic non-shivering thermogenesis in the intact animal is fully dependent on the presence of UCP1, and so is any kind of cold acclimation-recruited non-shivering thermogenesis; thus UCP2/UCP3 (or any other proteins or metabolic processes) cannot substitute for UCP1 physiologically, irrespective of their demonstrated ability to show uncoupling in reconstituted systems or when ectopically expressed. Norepinephrine-induced thermogenesis in brown-fat cells is absolutely dependent on UCP1, as is the uncoupled state and the recoupling by purine nucleotides in isolated brown-fat mitochondria. Although very high UCP2/UCP3 mRNA levels are observed in brown adipose tissue of UCP1-ablated mice, there is no indication that the isolated brown-fat mitochondria are uncoupled; thus, high expression of UCP2/UCP3 does not necessarily confer to the mitochondria of a tissue a propensity for being innately uncoupled. Whereas the thermogenic effect of fatty acids in brown-fat cells is fully UCP1-dependent, this is not the case in brown-fat mitochondria; this adds complexity to the issues concerning the mechanisms of UCP1 function and the pathway from beta(3)-adrenoceptor stimulation to UCP1 activation and thermogenesis. In addition to amino acid sequences conserved in all UCPs as part of the tripartite structure, all UCPs contain certain residues associated with nucleotide binding. However, conserved amongst all UCP1s so far sequenced, and without parallel in all UCP2/UCP3, are two sequences: 144SHLHGIKP and the C-terminal sequence RQTVDC(A/T)T; these sequences may therefore be essential for the unique thermogenic function of UCP1. The level of UCP1 in the organism is basically regulated at the transcriptional level (physiologically probably mainly through the beta(3)-adrenoceptor/CREB pathway), with influences from UCP1 mRNA stability and from the delay caused by translation. It is concluded that UCP1 is unique amongst the uncoupling proteins and is the only protein able to mediate adaptive non-shivering thermogenesis and the ensuing metabolic inefficiency.
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Affiliation(s)
- J Nedergaard
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
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12
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Matthias A, Ohlson KB, Fredriksson JM, Jacobsson A, Nedergaard J, Cannon B. Thermogenic responses in brown fat cells are fully UCP1-dependent. UCP2 or UCP3 do not substitute for UCP1 in adrenergically or fatty scid-induced thermogenesis. J Biol Chem 2000; 275:25073-81. [PMID: 10825155 DOI: 10.1074/jbc.m000547200] [Citation(s) in RCA: 261] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To examine the thermogenic significance of the classical uncoupling protein-1 (UCP1), the thermogenic potential of brown adipocytes isolated from UCP1-ablated mice was investigated. Ucp1(-/-) cells had a basal metabolic rate identical to wild-type; the mitochondria within them were coupled to the same degree. The response to norepinephrine in wild-type cells was robust ( approximately 10-fold increase in thermogenesis); Ucp1(-/-) cells only responded approximately 3% of this. Ucp1(-/-) cells were as potent as wild-type in norepinephrine-induced cAMP accumulation and lipolysis and had a similar mitochondrial respiratory complement. In wild-type cells, fatty acids induced a thermogenic response similar to norepinephrine, but fatty acids (and retinoate) were practically without effect in Ucp1(-/-) cells. It is concluded that no other adrenergically induced thermogenic mechanism exists in brown adipocytes except that mediated by UCP1 and that entopic expression of UCP1 does not lead to overt innate uncoupling, and it is suggested that fatty acids are transformed to an intracellular physiological activator of UCP1. High expression of UCP2 and UCP3 in the tissue was not associated with an overt innate highly uncoupled state of mitochondria within the cells, nor with an ability of norepinephrine or endo- or exogenous fatty acids to induce uncoupled respiration in the cells. Thus, UCP1 remains the only physiologically potent thermogenic uncoupling protein in these cells.
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Affiliation(s)
- A Matthias
- Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Sweden
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Matthias A, Jacobsson A, Cannon B, Nedergaard J. The bioenergetics of brown fat mitochondria from UCP1-ablated mice. Ucp1 is not involved in fatty acid-induced de-energization ("uncoupling"). J Biol Chem 1999; 274:28150-60. [PMID: 10497167 DOI: 10.1074/jbc.274.40.28150] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The bioenergetics of brown fat mitochondria isolated from UCP1-ablated mice were investigated. The mitochondria had lost the high GDP-binding capacity normally found in brown fat mitochondria, and they were innately in an energized state, in contrast to wild-type mitochondria. GDP, which led to energization of wild-type mitochondria, was without effect on the brown fat mitochondria from UCP1-ablated mice. The absence of thermogenic function did not result in reintroduction of high ATP synthase activity. Remarkably and unexpectedly, the mitochondria from UCP1-ablated mice were as sensitive to the de-energizing ("uncoupling") effect of free fatty acids as were UCP1-containing mitochondria. Therefore, the de-energizing effect of free fatty acids does not appear to be mediated via UCP1, and free fatty acids would not seem to be the intracellular physiological activator involved in mediation of the thermogenic signal from the adrenergic receptor to UCP1. In the UCP1-ablated mice, Ucp2 mRNA levels in brown adipose tissue were 14-fold higher and Ucp3 mRNA levels were marginally lower than in wild-type. The Ucp2 and Ucp3 mRNA levels were therefore among the highest found in any tissue. These high mRNA levels did not confer on the isolated mitochondria any properties associated with de-energization. Thus, the mere observation of a high level of Ucp2 or Ucp3 mRNA in a tissue cannot be taken as an indication that mitochondria isolated from that tissue will display innate de-energization or thermogenesis.
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Affiliation(s)
- A Matthias
- Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
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Chapter 17 The uncoupling protein thermogenin and mitochondrial thermogenesis. MOLECULAR MECHANISMS IN BIOENERGETICS 1992. [DOI: 10.1016/s0167-7306(08)60185-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Beta-adrenergic modulation of Ca2+ uptake by isolated brown adipocytes. Possible involvement of mitochondria. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)38009-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Mohell N, Connolly E, Nedergaard J. Distinction between mechanisms underlying alpha 1- and beta-adrenergic respiratory stimulation in brown fat cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1987; 253:C301-8. [PMID: 3618763 DOI: 10.1152/ajpcell.1987.253.2.c301] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Experimental conditions are described for selective alpha 1- and beta-adrenergic stimulation of the respiration of brown fat cells. The dual agonist norepinephrine was unsuitable as a selective alpha 1-agonist, since unacceptably high concentrations of propranolol were needed to abolish the beta-response. Phenylephrine at 50 microM, in the presence of 5 microM dl-propranolol, was shown to lead to a maximal, selective alpha 1-stimulation, whereas maximal, selective beta-stimulation was achieved with 1 microM isoproterenol in the presence of 5 microM prazosin. The mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) was able to further increase respiration that was already maximally alpha 1-stimulated, but when added before the alpha 1-stimulation, FCCP totally abolished the response. In contrast, FCCP had no effect on the beta-stimulated response. Similarly, oligomycin (an inhibitor of mitochondrial ATP synthesis) inhibited alpha 1-respiration but had a much smaller effect on beta-respiration. Ouabain (an inhibitor of the Na+-K+-ATPase) halved alpha 1-respiration but only induced a small inhibition of beta-respiration. It is concluded that only a small fraction of thermogenesis from beta-adrenergic processes is due to oxidative phosphorylation, whereas alpha 1-respiration is largely due to the oxygen cost of mitochondrial ATP synthesis, and a large fraction of this ATP is apparently used for the restoration of ion gradients.
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Connolly E, Nånberg E, Nedergaard J. Norepinephrine-induced Na+ influx in brown adipocytes is cyclic AMP-mediated. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)66880-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Kuusela P, Nedergaard J, Cannon B. Beta-adrenergic stimulation of fatty acid release from brown fat cells differentiated in monolayer culture. Life Sci 1986; 38:589-99. [PMID: 3003487 DOI: 10.1016/0024-3205(86)90052-4] [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: 01/03/2023]
Abstract
The ability of brown adipocytes differentiated in monolayer culture to respond to norepinephrine was investigated. It was found that fatty acid release in confluent brown adipocytes in monolayer culture was induced by norepinephrine, thus these cells were hormone-sensitive. After confluence, the rate of fatty acid release successively declined. The norepinephrine-stimulated fatty acid release was inhibited by propranolol, but not by phentolamine, indicating a mediation via beta-adrenergic receptors. It was concluded that there exist in the brown adipose tissue of nonfetal rats preadipocytes which possess the ability to express in culture a fully developed beta-adrenergic lipolytic response.
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Schneider-Picard G, Carpentier JL, Girardier L. Quantitative evaluation of gap junctions in rat brown adipose tissue after cold acclimation. J Membr Biol 1984; 78:85-9. [PMID: 6716453 DOI: 10.1007/bf01869196] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The decrease in the metabolic capacity of rat brown adipose tissue during the late postnatal period can be reversed by cold acclimation of the animals. In order to find out whether a parallel decrease in capability for intercellular communication observed during this period is also reversed by cold acclimation, gap junction size and number per unit area of cell surface have been quantified in freeze-fracture replicas; cell diameters have been measured in semi-thin sections. It was found that the specific number of gap junctions remains unchanged during cold acclimation. However, the mean gap junction size increases by 75% and the ratio of gap junctional area per cell volume, an index for intercellular exchange capacity, is doubled. This result illustrates further the parallelism between metabolic capacity and cell communication in brown fat.
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Huber CT, Duckworth WC, Solomon SS. The reversible inhibition by carbonyl cyanide m-chlorophenyl hydrazone of epinephrine-stimulated lipolysis in perifused isolated fat cells. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 666:462-7. [PMID: 7326256 DOI: 10.1016/0005-2760(81)90307-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Lipolysis stimulated in perifused isolated fat cells by 0.5 micrometers epinephrine is an ATP-dependent process which can be monitored by measuring the release of glycerol. The stimulated lipolysis is inhibited to 10 micrometers carbonyl cyanide m-chlorophenyl hydrazone (CCCP), an uncoupler of oxidative phosphorylation. If 20-micrometers glucose is continuously present in the perifusion medium during and after treatment with epinephrine and CCCP, the inhibition of the stimulated lipolysis is reversible when the CCCP is discontinued; otherwise it is not readily reversible. Since 20 micrometers 2-deoxyglucose will not substitute for glucose, metabolism of glucose beyond phosphorylation by hexokinase is concluded to be necessary in order to maintain the reversibility of the inhibition of CCCP. Substitution of 10 micrometers succinate for glucose also did not preserve the reversibility of the CCCP inhibition, and there was no significant difference in the amount of decrease of ATP in fat cells incubated with CCCP and epinephrine in the presence of glucose as compared to the decrease observed in the presence of succinate. The mechanism by which glucose maintains reversibility of the inhibition of stimulated lipolysis by CCCP is therefore not clear.
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Bukowiecki L, Folléa N, Lupien J, Paradis A. Metabolic relationships between lipolysis and respiration in rat brown adipocytes. The role of long chain fatty acids as regulators of mitochondrial respiration and feedback inhibitors of lipolysis. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)42972-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Kulinskii VI, Vorob'eva LM. Activation of respiration of liver mitochondria in various metabolic states by cyclic 3′,5′-AMP. Bull Exp Biol Med 1978. [DOI: 10.1007/bf00801342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The purpose of this study was to characterize the norepinephrine (NE)-evoked calorigenic response of an isolated perfused rat muscle preparation into alpha-and/or beta-adrenergic components. Epinephrine was as effective as NE in evoking the increase in oxygen consumption. The alpha-agonist, phenylephrine, was also as effective as NE in eliciting an increase in oxygen consumption by the muscle. Isoproterenol (beta-agonist) had no effect on the VO2 of the preparation. Phentolamine, an alpha-blocker, completely blocked the NE-stimulated VO2. Propranolol (beta-antagonist) could also completely block the NE induced VO2 but this drug was found to be less potent. It was concluded that the NE-induced calorigenic response of muscle cannot be classified either strictly as an alpha-or beta-response, but unlike brown adipose tissue, the alpha-response seems to predominate in skeletal muscle. Also, it appears as though different mechanisms of action may be involved in the NE-stimulated VO2 in skeletal muscle and brown fat.
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Pettersson B. CO2-mediated control of fatty acid metabolism in isolated hamster brown-fat cells during norepinephrine stimulation. EUROPEAN JOURNAL OF BIOCHEMISTRY 1977; 72:235-40. [PMID: 13995 DOI: 10.1111/j.1432-1033.1977.tb11244.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Addition of norepinephrine to isolated hamster brown-fat cells suspended in Krebs-Ringer phosphate buffer induces a pronounced, but temporary increase in respiratory rate. 2. If Krebs-Ringer phosphate buffer is bubbled with CO2 prior to the addition of cells and norepinephrine, the respiratory capacity of the cells is further potentiated and most important, the respiration is maintained at a high rate until the medium becomes depleted of oxygen. 3. This respiratory pattern cannot be obtained in CO2-bubbled Krebs-Ringer bicarbonate buffer. 4. The results indicate that CO2 has a regulatory effect on fatty acid metabolism in isolated hamster brown-fat cells.
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Bernstein J, Videla L, Israel Y. Role of the sodium pump in the regulation of liver metabolism in experimental alcoholism. Ann N Y Acad Sci 1974; 242:560-72. [PMID: 4279606 DOI: 10.1111/j.1749-6632.1974.tb19117.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Knight BL. Adenosine 3',5'-cyclic phosphate, lipolysis and oxygen consumption in brown adipose tissue from newborn rabbits. Effect of cervical sympathectomy and of noradrenalin and theophylline in vitro, and the partial purification of an adenosine 3',5'-cyclic phosphate-dependent protein kinase. BIOCHIMICA ET BIOPHYSICA ACTA 1974; 343:287-96. [PMID: 4365193 DOI: 10.1016/0304-4165(74)90093-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Fassina G, Dorigo P, Gaion RM. Equilibrium between metabolic pathways producing energy: a key factor in regulating lipolysis. PHARMACOLOGICAL RESEARCH COMMUNICATIONS 1974; 6:1-21. [PMID: 4372642 DOI: 10.1016/s0031-6989(74)80010-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Hittelman K, Bertin R, Butcher R. Cyclic AMP metabolism in brown adipocytes of hamsters exposed to different temperatures. Biochim Biophys Acta Gen Subj 1974. [DOI: 10.1016/0304-4165(74)90301-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Fassina G, Dorigo P, Perini G, Tóth E. Effect of glycolysis inhibitors on cyclic AMP synthesis in rat adipose tissue. Biochem Pharmacol 1972; 21:2295-301. [PMID: 4345896 DOI: 10.1016/0006-2952(72)90380-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Fassina G, Dorigo P, Badetti R, Visco L. Effect of oxidative phosphorylation inhibitors on cyclic adenosine monophosphate synthesis in rat adipose tissue. Biochem Pharmacol 1972; 21:1633-9. [PMID: 4345857 DOI: 10.1016/0006-2952(72)90313-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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ANGEL A, DESAI K, HALPERIN M. Reduction in adipocyte ATP by lipolytic agents: relation to intracellular free fatty acid accumulation. J Lipid Res 1971. [DOI: 10.1016/s0022-2275(20)39531-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Beviz A, Lundholm L, Mohme-Lundholm E. Cyclic AMP as a mediator of hormonal metabolic effects in brown adipose tissue. ACTA PHYSIOLOGICA SCANDINAVICA 1971; 81:145-56. [PMID: 4324124 DOI: 10.1111/j.1748-1716.1971.tb04886.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Skala J, Hahn P, Braun T. Adenyl cyclase activity in brown adipose tissue of young rats. LIFE SCIENCES. PT. 1: PHYSIOLOGY AND PHARMACOLOGY 1970; 9:1201-12. [PMID: 4320147 DOI: 10.1016/0024-3205(70)90153-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Fain JN, Loken SC, Czech MP. Oligomycin effects on lipolysis and the oxidative metabolism of brown fat cells. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 197:40-8. [PMID: 4312655 DOI: 10.1016/0005-2728(70)90006-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Himms-Hagen J. Regulation of metabolic processes in brown adipose tissue in relation to nonshivering thermogenesis. ADVANCES IN ENZYME REGULATION 1970; 8:131-51. [PMID: 4920377 DOI: 10.1016/0065-2571(70)90013-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Hollenberg CH, Vost A, Patten RL. Regulation of adipose mass: control of fat cell development and lipid content. RECENT PROGRESS IN HORMONE RESEARCH 1970; 26:463-503. [PMID: 4319351 DOI: 10.1016/b978-0-12-571126-5.50015-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Spectroscopic Evidence for the Control of Respiration Prior to Phosphorylation in Hamster Brown Fat Cells. J Biol Chem 1970. [DOI: 10.1016/s0021-9258(18)63403-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Christiansen EN, Pedersen JI, Grav HJ. Uncoupling and recoupling of oxidative phosphorylation in brown adipose tissue mitochondria. Nature 1969; 222:857-60. [PMID: 5770525 DOI: 10.1038/222857a0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Reed N, Fain JN. Potassium-dependent Stimulation of Respiration in Brown Fat Cells by Fatty Acids and Lipolytic Agents. J Biol Chem 1968. [DOI: 10.1016/s0021-9258(18)94462-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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