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Carpéné C, Marti L, Morin N. Increased monoamine oxidase activity and imidazoline binding sites in insulin-resistant adipocytes from obese Zucker rats. World J Biol Chem 2022; 13:15-34. [PMID: 35126867 PMCID: PMC8790288 DOI: 10.4331/wjbc.v13.i1.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/09/2021] [Accepted: 01/14/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Despite overt insulin resistance, adipocytes of genetically obese Zucker rats accumulate the excess of calorie intake in the form of lipids.
AIM To investigate whether factors can replace or reinforce insulin lipogenic action by exploring glucose uptake activation by hydrogen peroxide, since it is produced by monoamine oxidase (MAO) and semicarbazide-sensitive amine oxidase (SSAO) in adipocytes.
METHODS 3H-2-deoxyglucose uptake (2-DG) was determined in adipocytes from obese and lean rats in response to insulin or MAO and SSAO substrates such as tyramine and benzylamine. 14C-tyramine oxidation and binding of imidazolinic radioligands [3H-Idazoxan, 3H-(2-benzofuranyl)-2-imidazoline] were studied in adipocytes, the liver, and muscle. The influence of in vivo administration of tyramine + vanadium on glucose handling was assessed in lean and obese rats.
RESULTS 2-DG uptake and lipogenesis stimulation by insulin were dampened in adipocytes from obese rats, when compared to their lean littermates. Tyramine and benzylamine activation of hexose uptake was vanadate-dependent and was also limited, while MAO was increased and SSAO decreased. These changes were adipocyte-specific and accompanied by a greater number of imidazoline I2 binding sites in the obese rat, when compared to the lean. In vitro, tyramine precluded the binding to I2 sites, while in vivo, its administration together with vanadium lowered fasting plasma levels of glucose and triacylglycerols in obese rats.
CONCLUSION The adipocytes from obese Zucker rats exhibit increased MAO activity and imidazoline binding site number. However, probably as a consequence of SSAO down-regulation, the glucose transport stimulation by tyramine is decreased as much as that of insulin in these insulin-resistant adipocytes. The adipocyte amine oxidases deserve more studies with respect to their putative contribution to the management of glucose and lipid handling.
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Affiliation(s)
- Christian Carpéné
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM, Toulouse 31342, France
| | - Luc Marti
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM, Toulouse 31342, France
| | - Nathalie Morin
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM, Toulouse 31342, France
- Faculté de Pharmacie de Paris, Paris University, Paris 75270, France
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Snook LA, Trottier SK, Worndl EA, Bombardier E, Tupling AR, MacPherson REK. Prior Endurance Training Enhances Beta-Adrenergic Signaling in Epidydimal Adipose from Mice Fed a High-Fat Diet. Obesity (Silver Spring) 2017; 25:1699-1706. [PMID: 28857453 DOI: 10.1002/oby.21933] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/04/2017] [Accepted: 06/20/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Adipose tissue beta-adrenergic signaling is attenuated in obesity and insulin resistance. It has been previously demonstrated that prior exercise training protects against short-term, high-fat diet (HFD)-induced weight gain and glucose intolerance. This study aimed to determine whether prior exercise training results in altered beta-adrenergic and lipolytic signaling in adipose tissue when challenged with a HFD. METHODS Male C57BL/6J mice underwent 4 weeks of treadmill training (1 h/d, 5 d/wk). Twenty-four hours after the final bout of exercise, mice were fed a HFD (60% kcal lard) for 4 days. RESULTS Serum fatty acids, beta-adrenergic signaling (phosphorylated ERK, hormone-sensitive lipase, and p38), and perilipin 1 content were greater in epididymal white adipose tissue (eWAT) from previously trained mice. These changes were not evident in eWAT from trained mice prior to the HFD and were not secondary to alterations in insulin responsiveness or catecholamine concentrations. CL 316,243-mediated increases in hormone-sensitive lipase phosphorylation and fatty acid accumulation in the media were greater in adipose tissue explants from previously trained mice fed a HFD. CONCLUSIONS These findings suggest that previous training increases adipose tissue beta-adrenergic responsiveness to a short-term HFD. This may help to explain the protective effect of prior exercise training against the deleterious effects of a HFD.
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Affiliation(s)
- Laelie A Snook
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Sarah K Trottier
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Elizabeth A Worndl
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Tang L, Okamoto S, Shiuchi T, Toda C, Takagi K, Sato T, Saito K, Yokota S, Minokoshi Y. Sympathetic Nerve Activity Maintains an Anti-Inflammatory State in Adipose Tissue in Male Mice by Inhibiting TNF-α Gene Expression in Macrophages. Endocrinology 2015; 156:3680-94. [PMID: 26132918 DOI: 10.1210/en.2015-1096] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Adipose tissue macrophages (ATMs) play an important role in the inflammatory response in obese animals. How ATMs are regulated in lean animals has remained elusive, however. We now show that the sympathetic nervous system (SNS) is necessary to maintain the abundance of the mRNA for the proinflammatory cytokine TNF-α at a low level in ATMs of lean mice. Intracerebroventricular injection of agouti-related neuropeptide increased the amount of TNF-α mRNA in epididymal (epi) white adipose tissue (WAT), but not in interscapular brown adipose tissue (BAT), through inhibition of sympathetic nerve activity in epiWAT. The surgical denervation and β-adrenergic antagonist propranolol up-regulated TNF-α mRNA in both epiWAT and BAT in vivo. Signaling by the β2-adrenergic receptor (AR) and protein kinase A down-regulated TNF-α mRNA in epiWAT explants and suppressed lipopolysaccharide-induced up-regulation of TNF-α mRNA in the stromal vascular fraction of this tissue. β-AR-deficient (β-less) mice manifested an increased plasma TNF-α concentration and increased TNF-α mRNA abundance in epiWAT and BAT. TNF-α mRNA abundance was greater in ATMs (CD11b(+) cells of the stromal vascular fraction) from epiWAT or BAT of wild-type mice than in corresponding CD11b(-) cells, and β2-AR mRNA abundance was greater in ATMs than in CD11b(-) cells of epiWAT. Our results show that the SNS and β2-AR-protein kinase A pathway maintain an anti-inflammatory state in ATMs of lean mice in vivo, and that the brain melanocortin pathway plays a role in maintaining this state in WAT of lean mice via the SNS.
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MESH Headings
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/innervation
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/innervation
- Adipose Tissue, White/metabolism
- Adrenergic beta-Antagonists/pharmacology
- Agouti-Related Protein/administration & dosage
- Animals
- Cell Line
- Epididymis/drug effects
- Epididymis/metabolism
- Gene Expression/drug effects
- Immunoblotting
- Inflammation Mediators/metabolism
- Injections, Intraventricular
- Macrophages/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Peptide Fragments/administration & dosage
- Propranolol/pharmacology
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sympathectomy
- Sympathetic Nervous System/metabolism
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Lijun Tang
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Shiki Okamoto
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Tetsuya Shiuchi
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Chitoku Toda
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Kazuyo Takagi
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Tatsuya Sato
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Kumiko Saito
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Shigefumi Yokota
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
| | - Yasuhiko Minokoshi
- Division of Endocrinology and Metabolism (L.T., S.O., K.T., T.Sa., K.S., S.Y., Y.M.), Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences (S.O., T.Sa., Y.M.), Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan; Department of Integrative Physiology (T.Sh.), Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima City, Tokushima 770-8503, Japan; and Section of Comparative Medicine (C.T.), Yale University School of Medicine, New Haven, Connecticut 06520-8016
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Alemzadeh R, Karlstad MD, Tushaus K, Buchholz M. Diazoxide enhances basal metabolic rate and fat oxidation in obese Zucker rats. Metabolism 2008; 57:1597-607. [PMID: 18940400 DOI: 10.1016/j.metabol.2008.06.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Accepted: 06/13/2008] [Indexed: 11/26/2022]
Abstract
Persistent suppression of hyperinsulinemia in genetically obese (fa/fa) Zucker rats by diazoxide (DZ) reduces food intake and weight gain; improves insulin sensitivity, glycemic control, and lipid profile; and enhances beta(3)-adrenergic function and lipolysis in adipose tissue. The aim of this study was to elucidate the effects of DZ on basal metabolic rate (BMR), fat oxidation, and adrenergic function of lean and obese Zucker rats. Diazoxide (150 mg/kg/d) or vehicle (control) was administered for 4 weeks in 7-week-old obese and lean Zucker rats (n = 8-9 per subgroup). Animals underwent indirect calorimetry, body composition analysis, and determination of uncoupling proteins (UCPs) messenger RNA (mRNA) in brown and white adipose tissues (BAT and WAT) and skeletal muscle (SM), beta(3)-adrenergic receptor (AR) mRNA in BAT and WAT, beta(2)-AR in SM as well as WAT, and SM adenylate cyclase (AC) activity at the completion of study. Diazoxide treatment decreased food intake, weight gain, and body fat in obese rats (P < .01). Although DZ treatment lowered fasting plasma glucose, insulin, leptin, adiponectin, and lipids in obese rats (P < .01), it increased adiponectin-leptin ratio (P < .01). Plasma adiponectin-leptin ratio was inversely correlated with fat mass in obese and lean rats (r = -0.86, P < .0001). Diazoxide treatment resulted in higher BMR and fat oxidation rate in obese compared with control animals (P < .01), without any effect in lean animals. Furthermore, plasma adiponectin was inversely correlated with BMR (-0.56, P < .001) and lipid oxidation rate (-0.61, P < .0005) and was positively correlated with nonprotein respiratory quotient (r = 0.41, P < .01) in obese and lean rats. This was associated with increased beta(3)-AR mRNA expression in BAT and WAT (P < .01), UCP-1 and UCP-3 in BAT and AC activity in WAT (P < .02), and AC activity in SM of DZ obese rats compared with controls (P < .01), without significant change in SM beta(2)-AR mRNA expressions. Diazoxide attenuation of hyperinsulinemia decreased the rate of weight gain but enhanced insulin sensitivity, BMR, and fat oxidation in obese rats. This was associated with increased receptor- and non-receptor-mediated adrenergic function in adipose and muscle tissues in obese rats, respectively. These metabolic changes in obese Zucker rats suggest that antiobesity effects of DZ appear to be not only through its anorectic effect, modification of disturbed insulin metabolism, and inhibition of lipogenesis, but also due to augmentation of adrenergic function, energy expenditure, and fat utilization.
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Affiliation(s)
- Ramin Alemzadeh
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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