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Takahashi K, Kitaoka Y, Hatta H. Effects of endurance training on metabolic enzyme activity and transporter protein levels in the skeletal muscles of orchiectomized mice. J Physiol Sci 2022; 72:14. [PMID: 35768774 PMCID: PMC10717707 DOI: 10.1186/s12576-022-00839-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 06/18/2022] [Indexed: 12/20/2022]
Abstract
This study investigated whether endurance training attenuates orchiectomy (ORX)-induced metabolic alterations. At 7 days of recovery after sham operation or ORX surgery, the mice were randomized to remain sedentary or undergo 5 weeks of treadmill running training (15-20 m/min, 60 min, 5 days/week). ORX decreased glycogen concentration in the gastrocnemius muscle, enhanced phosphofructokinase activity in the plantaris muscle, and decreased lactate dehydrogenase activity in the plantaris and soleus muscles. Mitochondrial enzyme activities and protein content in the plantaris and soleus muscles were also decreased after ORX, but preserved, in part, by endurance training. In the treadmill running test (15 m/min, 60 min) after 4 weeks of training, orchiectomized sedentary mice showed impaired exercise performance, which was restored by endurance training. Thus, endurance training could be a potential therapeutic strategy to prevent the hypoandrogenism-induced decline in muscle mitochondrial content and physical performance.
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Affiliation(s)
- Kenya Takahashi
- Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
| | - Yu Kitaoka
- Department of Human Sciences, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama, Kanagawa, 221-8686, Japan
| | - Hideo Hatta
- Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
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2
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Interactions between insulin and exercise. Biochem J 2021; 478:3827-3846. [PMID: 34751700 DOI: 10.1042/bcj20210185] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 02/06/2023]
Abstract
The interaction between insulin and exercise is an example of balancing and modifying the effects of two opposing metabolic regulatory forces under varying conditions. While insulin is secreted after food intake and is the primary hormone increasing glucose storage as glycogen and fatty acid storage as triglycerides, exercise is a condition where fuel stores need to be mobilized and oxidized. Thus, during physical activity the fuel storage effects of insulin need to be suppressed. This is done primarily by inhibiting insulin secretion during exercise as well as activating local and systemic fuel mobilizing processes. In contrast, following exercise there is a need for refilling the fuel depots mobilized during exercise, particularly the glycogen stores in muscle. This process is facilitated by an increase in insulin sensitivity of the muscles previously engaged in physical activity which directs glucose to glycogen resynthesis. In physically trained individuals, insulin sensitivity is also higher than in untrained individuals due to adaptations in the vasculature, skeletal muscle and adipose tissue. In this paper, we review the interactions between insulin and exercise during and after exercise, as well as the effects of regular exercise training on insulin action.
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3
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Li L, Zhu Y, Wu J, Hinkle SN, Tobias DK, Ma RCW, Weir NL, Tsai MY, Zhang C. Changes of Plasma Phospholipid Fatty Acids Profiles in Pregnancy in Relation to the Diagnosis and Treatment of Gestational Diabetes Mellitus. Clin Chem 2021; 67:1660-1675. [PMID: 34632496 DOI: 10.1093/clinchem/hvab169] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/21/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Plasma phospholipid fatty acids (FAs) in early and mid-pregnancy have been prospectively related to gestational diabetes mellitus (GDM) risk. Yet, changes of FAs following GDM diagnosis and treatment and their implications for glucose metabolism and control remain understudied. METHODS From the Eunice Kennedy Shriver National Institute Child Health and Human Development Fetal Growth Studies-Singleton Cohort of 2802 pregnant women, we ascertained 85 GDM cases using the Carpenter and Coustan criteria and 85 non-GDM controls after exclusion. Using plasma collected before (23-31 weeks) and after GDM diagnosis (33-39 weeks), we quantified 25 saturated, poly- and monounsaturated FAs levels. We estimated the fold change of FAs before and after GDM diagnosis, using multiple linear mixed models adjusting for confounders. RESULTS Eight FAs showed significant fold changes from the baseline values (23-31 weeks) among GDM cases as compared to women without GDM. Five FAs showed reduced fold changes [myristic acid (14:0): β: -0.22 (95% CI: -0.30, -0.14), palmitic acid (16:0): β: -0.02 (95% CI: -0.04, -0.01), cis-palmitoleic acid (16:1n7): β: -0.15 (95% CI: -0.24, -0.05), alpha-linolenic acid (18:3n3): β: -0.19 (95% CI: -0.31, -0.07], and dihomo-gamma-linoleic acid (20:3n6): β:-0.16; 95% CI: -0.21, -0.11)], whereas 3 showed increases [heptadecanoic acid (17:0): β: 0.17 (95% CI: 0.11, 0.22), cis-vaccenic acid (18:1n7): β: 0.06 (95% CI: 0.03, 0.10), and arachidonic acid (20:4n6): β: 0.10 (95% CI: 0.06, 0.13)]. CONCLUSIONS Our study identified 8 FAs with unique patterns of change before and after GDM diagnosis that differed significantly between women with and without GDM. Our findings may shed light on the role of FA metabolism in the pathophysiology and disease management and progression of GDM. CLINICAL TRIAL REGISTRY NCT00912132.
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Affiliation(s)
- Lingjun Li
- Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yeyi Zhu
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.,Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA
| | - Jing Wu
- Glotech Inc., Bethesda, MD, USA
| | - Stefanie N Hinkle
- Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Deirdre K Tobias
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Ronald C W Ma
- Division of Endocrinology & Diabetes, Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
| | - Natalie L Weir
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Michael Y Tsai
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Cuilin Zhang
- Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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4
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Abstract
As the principal tissue for insulin-stimulated glucose disposal, skeletal muscle is a primary driver of whole-body glycemic control. Skeletal muscle also uniquely responds to muscle contraction or exercise with increased sensitivity to subsequent insulin stimulation. Insulin's dominating control of glucose metabolism is orchestrated by complex and highly regulated signaling cascades that elicit diverse and unique effects on skeletal muscle. We discuss the discoveries that have led to our current understanding of how insulin promotes glucose uptake in muscle. We also touch upon insulin access to muscle, and insulin signaling toward glycogen, lipid, and protein metabolism. We draw from human and rodent studies in vivo, isolated muscle preparations, and muscle cell cultures to home in on the molecular, biophysical, and structural elements mediating these responses. Finally, we offer some perspective on molecular defects that potentially underlie the failure of muscle to take up glucose efficiently during obesity and type 2 diabetes.
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5
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Samkani A, Skytte MJ, Anholm C, Astrup A, Deacon CF, Holst JJ, Madsbad S, Boston R, Krarup T, Haugaard SB. The acute effects of dietary carbohydrate reduction on postprandial responses of non-esterified fatty acids and triglycerides: a randomized trial. Lipids Health Dis 2018; 17:295. [PMID: 30591062 PMCID: PMC6309080 DOI: 10.1186/s12944-018-0953-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 12/18/2018] [Indexed: 02/08/2023] Open
Abstract
Background Postprandial non-esterified fatty acid (NEFA) and triglyceride (TG) responses are increased in subjects with type 2 diabetes mellitus (T2DM) and may impair insulin action and increase risk of cardiovascular disease and death. Dietary carbohydrate reduction has been suggested as non-pharmacological therapy for T2DM, but the acute effects on NEFA and TG during subsequent meals remain to be investigated. Methods Postprandial NEFA and TG responses were assessed in subjects with T2DM by comparing a carbohydrate-reduced high-protein (CRHP) diet with a conventional diabetes (CD) diet in an open-label, randomized, cross-over study. Each diet was consumed on two consecutive days, separated by a wash-out period. The iso-caloric CRHP/CD diets contained 31/54 E% from carbohydrate, 29/16 E% energy from protein and 40/30 E% from fat, respectively. Sixteen subjects with well-controlled T2DM (median HbA1c 47 mmol/mol, (37–67 mmol/mol) and BMI 30 ± 4.4 kg/m2) participated in the study. NEFA and TG were evaluated following breakfast and lunch. Results NEFA net area under curve (AUC) was increased by 97 ± 38 μmol/Lx270 min (p = 0.024) after breakfast but reduced by 141 ± 33 μmol/Lx180 min (p < 0.001) after lunch on the CRHP compared with CD diet. Likewise, TG net AUC was increased by 80 ± 28 μmol/Lx270 min (p = 0.012) after breakfast but reduced by 320 ± 60 μmol/Lx180 min (p < 0.001) after lunch on the CRHP compared with CD diet. Conclusions In well-controlled T2DM a modest reduction of dietary carbohydrate with a corresponding increase in protein and fat acutely reduced postprandial serum NEFA suppression and increased serum TG responses after a breakfast meal but had the opposite effect after a lunch meal. The mechanism behind this second-meal phenomenon of CRHP diet on important risk factors for aggravating T2DM and cardiovascular disease awaits further investigation. Trial registration The study was registered at clinicaltrials.gov ID: NCT02472951. https://clinicaltrials.gov/ct2/show/NCT02472951. Registered June 16, 2015.
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Affiliation(s)
- Amirsalar Samkani
- Department of Endocrinology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark.
| | - Mads J Skytte
- Department of Endocrinology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - Christian Anholm
- Department of Internal Medicine, Copenhagen University Hospital, Glostrup, Denmark
| | - Arne Astrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Carolyn F Deacon
- Endocrinology Research Section, Department of Biomedical Sciences, Copenhagen, Denmark.,Section for Translational Physiology, Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Endocrinology Research Section, Department of Biomedical Sciences, Copenhagen, Denmark.,Section for Translational Physiology, Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Sten Madsbad
- Department of Endocrinology, Copenhagen University Hospital, Amager Hvidovre, Copenhagen, Denmark
| | - Ray Boston
- School of Medicine, Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Thure Krarup
- Department of Endocrinology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - Steen B Haugaard
- Department of Endocrinology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark.,Department of Internal Medicine, Copenhagen University Hospital, Amager Hvidovre, Copenhagen, Denmark
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6
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Samkani A, Skytte MJ, Thomsen MN, Astrup A, Deacon CF, Holst JJ, Madsbad S, Rehfeld JF, Krarup T, Haugaard SB. Acute Effects of Dietary Carbohydrate Restriction on Glycemia, Lipemia and Appetite Regulating Hormones in Normal-Weight to Obese Subjects. Nutrients 2018; 10:nu10091285. [PMID: 30213037 PMCID: PMC6163561 DOI: 10.3390/nu10091285] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 12/26/2022] Open
Abstract
Postprandial responses to food are highly dependent on the macronutrient composition of the diet. We investigated the acute effects of transition from the recommended moderately high carbohydrate (HC) diet towards a carbohydrate-reduced high-protein (CRHP) diet on postprandial glycemia, insulinemia, lipemia, and appetite-regulating hormones in non-diabetic adults. Fourteen subjects, including five males (Mean ± SD: age 62 ± 6.5; BMI 32 ± 7.6 kg/m2; hemoglobin A1c (HbA1c) 40 ± 3.0 mmol/mol; HOMA2-IR 2.1 ± 0.9) were included in this randomized, cross-over study. Iso-caloric diets were consumed for two consecutive days with a median wash-out period of 21 days (range 2–8 weeks) between diets (macronutrient energy composition: CRHP/HC; 31%/54% carbohydrate, 29%/16% protein, 40%/30% fat). Postprandial glucose, insulin secretion rate (ISR), triglycerides (TGs), non-esterified fatty acids (NEFAs), and satiety ratings were assessed after ingestion of breakfast (Br) and lunch (Lu), and gut hormones and glucagon were assessed after ingestion of Br. Compared with the HC diet, the CRHP diet reduced peak glucose concentrations (Br 11%, p = 0.024; Lu 11%, p < 0.001), glucose excursions (Br 80%, p = 0.20; Lu 85%, p < 0.001), and ISR (Br 31%; Lu 64%, both p < 0.001) whereas CRHP, as compared with HC, increased glucagon-like peptide-1 (Br 27%, p = 0.015) and glucagon values (Br 249%, p < 0.001). NEFA and TG levels increased in the CRHP diet as compared with the HC diet after Br, but no difference was found after Lu (NEFA Br 22%, p < 0.01; TG Br 42%, p = 0.012). Beta-cell glucose sensitivity, insulin clearance, cholecystokinin values, and subjective satiety ratings were unaffected. It is possible to achieve a reduction in postprandial glycemia and insulin without a deleterious effect on beta-cell glucose sensitivity by substituting part of dietary carbohydrate with iso-caloric protein and fat in subjects without type 2 diabetes mellitus (T2DM). The metabolic effects are more pronounced after the second meal.
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Affiliation(s)
- Amirsalar Samkani
- Department of Endocrinology, Copenhagen University Hospital, Bispebjerg, DK-2400 Copenhagen NV, Denmark.
| | - Mads J Skytte
- Department of Endocrinology, Copenhagen University Hospital, Bispebjerg, DK-2400 Copenhagen NV, Denmark.
| | - Mads N Thomsen
- Department of Endocrinology, Copenhagen University Hospital, Bispebjerg, DK-2400 Copenhagen NV, Denmark.
| | - Arne Astrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, DK-1017 Copenhagen K, Denmark.
| | - Carolyn F Deacon
- Endocrinology Research Section, Department of Biomedical Sciences, University of Copenhagen, DK-1017 Copenhagen K, Denmark.
- Section for Translational Physiology, NNF Center for Basic Metabolic Research, University of Copenhagen, DK-1017 Copenhagen K, Denmark.
| | - Jens J Holst
- Endocrinology Research Section, Department of Biomedical Sciences, University of Copenhagen, DK-1017 Copenhagen K, Denmark.
- Section for Translational Physiology, NNF Center for Basic Metabolic Research, University of Copenhagen, DK-1017 Copenhagen K, Denmark.
| | - Sten Madsbad
- Department of Endocrinology, Copenhagen University Hospital, Amager Hvidovre, DK-2650 Hvidovre, Denmark.
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark.
| | - Thure Krarup
- Department of Endocrinology, Copenhagen University Hospital, Bispebjerg, DK-2400 Copenhagen NV, Denmark.
| | - Steen B Haugaard
- Department of Endocrinology, Copenhagen University Hospital, Bispebjerg, DK-2400 Copenhagen NV, Denmark.
- Department of Internal Medicine, Copenhagen University Hospital, Amager Hvidovre, DK-2650 Hvidovre, Denmark.
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7
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Luo G, Feng Y, Zhang J, Mu Q, Shi Y, Qin L, Zheng L, Berggren-Söderlund M, Nilsson-Ehle P, Zhang X, Xu N. Rosiglitazone enhances apolipoprotein M (Apom) expression in rat's liver. Int J Med Sci 2014; 11:1015-21. [PMID: 25136257 PMCID: PMC4135224 DOI: 10.7150/ijms.8330] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/14/2014] [Indexed: 11/17/2022] Open
Abstract
Apolipoprotein M (APOM) has been suggested as a vasculoprotective constituent of high density lipoprotein (HDL), which plays a crucial role behind the mechanism of HDL-mediated anti-atherosclerosis. Previous studies demonstrated that insulin resistance could associate with decreased APOM expressions. In agreement with our previous reports, here, we further confirmed that the insulin sensitivity was also reduced in rats treated with high concentrations of glucose; such effect could be reversed by administration of rosiglitazone, a peroxisome proliferator-activated receptor-γ (PPARγ). The present study shows that Apom expression is significantly affected by either rosiglitazone or hyperglycemia alone without cross interaction with each other, which indicates that the pathway of Apom expression regulating by hyperglycemia might be differed from that by rosiglitazone. Further study indicated that hyperglycemia could significantly inhibit mRNA levels of Lxrb (P=0.0002), small heterodimer partner 1 (Shp1) (P<0.0001), liver receptor homologue-1 (Lrh1) (P=0.0012), ATP-binding cassette transporter 1 (Abca1) (P=0.0012) and Pparb/d (P=0.0043). Two-way ANOVA analysis demonstrated that the interactions between rosiglitazone and infusion of 25% glucose solution on Shp1 (P=0.0054) and Abca1 (4E, P=0.0004) mRNA expression was statistically significant. It is concluded that rosiglitazone could increase Apom expression, of which the detailed mechanism needs to be further investigated. The downregulation of Apom by hyperglycemia might be mainly through decreasing expression of Pparg and followed by inhibiting Lxrb in rats.
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Affiliation(s)
- Guanghua Luo
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Yuehua Feng
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Jun Zhang
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Qinfeng Mu
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Yuanping Shi
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Li Qin
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Lu Zheng
- 1. Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Maria Berggren-Söderlund
- 3. Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lunds University, S-221 85 Lund, Sweden
| | - Peter Nilsson-Ehle
- 3. Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lunds University, S-221 85 Lund, Sweden
| | - Xiaoying Zhang
- 2. Department of Cardiothoracic Surgery, the Third Affiliated Hospital of Soochow University, Changzhou 213003, P.R. China
| | - Ning Xu
- 3. Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lunds University, S-221 85 Lund, Sweden
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8
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Chandalia M, Davila H, Pan W, Szuszkiewicz M, Tuvdendorj D, Livingston EH, Abate N. Adipose tissue dysfunction in humans: a potential role for the transmembrane protein ENPP1. J Clin Endocrinol Metab 2012; 97:4663-72. [PMID: 23012391 PMCID: PMC3513530 DOI: 10.1210/jc.2012-2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
CONTEXT Adipose tissue (AT) helps to regulate body fat partitioning and systemic lipid/glucose metabolism. We have recently reported lipid/glucose metabolism abnormalities and increased liver triglyceride content in an AT-selective transgenic model overexpressing ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1), the AdiposeENPP1-Tg mouse. OBJECTIVE The aim of the study was to test the translational hypothesis that AT-ENPP1 overexpression associates with AT dysfunction (changes in AT gene expression, plasma fatty acid, and adipokine levels), increased liver triglyceride deposition, and systemic insulin resistance in humans. DESIGN/SETTING/PARTICIPANTS A total of 134 young normoglycemic men and women were subjected to body composition studies, hyperinsulinemic-euglycemic clamps, and AT needle biopsy. Twenty men also had liver/muscle nuclear magnetic resonance spectroscopy. MAIN OUTCOME MEASURES Predetermined measures included AT expression of ENPP1 and other lipid metabolism/inflammation genes, plasma adipokines, and nonesterified fatty acid (NEFA) levels, liver/muscle triglyceride content, and the systemic glucose disposal rate. RESULTS After statistical adjustment for body fat content, increasing AT-ENPP1 was associated with up-regulation of genes involved in NEFA metabolism and inflammation, increased postabsorptive NEFA levels, decreased plasma adiponectin, increased liver triglyceride content, and systemic insulin resistance in men. In women, there were no changes in plasma adiponectin, NEFAs, or glucose disposal rate associated with increasing AT-ENPP1, despite increased expression of lipid metabolism and inflammation genes in AT. CONCLUSIONS Increased AT-ENPP1 is associated with AT dysfunction, increased liver triglyceride deposition, and systemic insulin resistance in young normoglycemic men. These findings are concordant with the AdiposeENPP1-Tg phenotype and identify a potential target of therapy for health complications of AT dysfunction, including type 2 diabetes and cardiovascular disease.
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Affiliation(s)
- Manisha Chandalia
- Department of Medicine, Division of Endocrinology, University of Texas Medical Branch at Galveston, Texas 77555-1060, USA
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9
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Freemantle E, Vandal M, Tremblay Mercier J, Plourde M, Poirier J, Cunnane SC. Metabolic response to a ketogenic breakfast in the healthy elderly. J Nutr Health Aging 2009; 13:293-8. [PMID: 19300863 DOI: 10.1007/s12603-009-0026-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE To determine whether the metabolism of glucose or ketones differs in the healthy elderly compared to young or middle-aged adults during mild, short-term ketosis induced by a ketogenic breakfast. DESIGN AND PARTICIPANTS Healthy subjects in three age groups (23 +/- 1, 50 +/- 1 and 76 +/- 2 y old) were given a ketogenic meal and plasma beta -hydroxybutyrate, glucose, insulin, triacylglycerols, total cholesterol, non-esterified fatty acids and breath acetone were measured over the subsequent 6 h. Each subject completed the protocol twice in order to determine the oxidation of a tracer dose of both carbon-13 (13C) glucose and 13C-beta-hydroxybutyrate. The tracers were given separately in random order. Apolipoprotein E genotype was also determined in all subjects. RESULTS Plasma glucose decreased and beta-hydroxybutyrate, acetone and insulin increased similarly over 6 h in all three groups after the ketogenic meal. There was no significant change in cholesterol, triacylglycerols or non-esterified fatty acids over the 6 h. 13C-glucose and 13C-beta-hydroxybutyrate oxidation peaked at 2-3 h postdose for all age groups. Cumulative 13C-glucose oxidation over 24 h was significantly higher in the elderly but only versus the middle-aged group. There was no difference in cumulative 13C-beta-hydroxybutyrate oxidation between the three groups. Apolipoprotein E (epsilon 4) was associated with elevated fasting cholesterol but was unrelated to the other plasma metabolites. CONCLUSION Elderly people in relatively good health have a similar capacity to produce ketones and to oxidize 13C-beta-hydroxybutyrate as middle-aged or young adults, but oxidize 13C-glucose a little more rapidly than healthy middle-aged adults.
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Affiliation(s)
- E Freemantle
- Research Center on Aging, Health, and Social Services Center, Sherbrooke University Geriatrics Institute, 1036 Belvédère S., Sherbrooke, QC, Canada
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10
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Malipa ACA, Meintjes RA, Haag M. Arachidonic acid and glucose uptake by freshly isolated human adipocytes. Cell Biochem Funct 2008; 26:221-7. [PMID: 17708582 DOI: 10.1002/cbf.1439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fatty acid (FA) and glucose transport into insulin-dependent cells are impaired in insulin resistance (IR; type 2 diabetes mellitus). Studies done on the effects of FAs on glucose uptake, and the influence of insulin on FA uptake by adipocytes, have yielded contradictory results. In this study, isolated human adipocytes were exposed to arachidonic acid (AA) and to insulin, and FA uptake as well as glucose uptake was measured. AA uptake into adipocyte membranes and nuclei was also investigated. Glucose uptake was inhibited by 57 +/- 8% after 30 min of exposure to arachidonate. AA was significantly taken up into adipocyte membranes (49.6 +/- 29% and 123 +/- 74%) at 20 and 30 min of exposure, respectively, and into nuclei (147.6 +/- 19.2%) after 30 min. Insulin stimulated AA uptake (24.1 +/- 14.1%) at 30 min by adipocytes from a non-obese subject, while inhibiting it (16.6 +/- 12%) in adipocytes from an obese subject. These results suggest that: (1) AA inhibits glucose uptake by adipocytes exposed over a short period, probably by a membrane-associated mechanism, (2) insulin-dependent AA uptake is dependent on the body mass index (BMI) of the donor and the insulin sensitivity of their adipocytes.
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Affiliation(s)
- Ana C A Malipa
- Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, South Africa
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11
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Koutsari C, Jensen MD. Thematic review series: Patient-Oriented Research. Free fatty acid metabolism in human obesity. J Lipid Res 2006; 47:1643-50. [PMID: 16685078 DOI: 10.1194/jlr.r600011-jlr200] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Adipose tissue lipolysis provides circulating FFAs to meet the body's lipid fuel demands. FFA release is well regulated in normal-weight individuals; however, in upper-body obesity, excess lipolysis is commonly seen. This abnormality is considered a cause for at least some of the metabolic defects (dyslipidemia, insulin resistance) associated with upper-body obesity. "Normal" lipolysis is sex-specific and largely determined by the individual's resting metabolic rate. Women have greater FFA release rates than men without higher FFA concentrations or greater fatty acid oxidation, indicating that they have greater nonoxidative FFA disposal, although the processes and tissues involved in this phenomenon are unknown. Therefore, women have the advantage of having greater FFA availability without exposing their tissues to higher and potentially harmful FFA concentrations. Upper-body fat is more lipolytically active than lower-body fat in both women and men. FFA released by the visceral fat depot contributes only a small percentage of systemic FFA delivery. Upper-body subcutaneous fat is the dominant contributor to circulating FFAs and the source of the excess FFA release in upper-body obesity. We believe that abnormalities in subcutaneous lipolysis could be more important than those in visceral lipolysis as a cause of peripheral insulin resistance. Understanding the regulation of FFA availability will help to discover new approaches to treat FFA-induced abnormalities in obesity.
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12
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Boden G, Cheung P, Mozzoli M, Fried SK. Effect of thiazolidinediones on glucose and fatty acid metabolism in patients with type 2 diabetes. Metabolism 2003; 52:753-9. [PMID: 12800103 DOI: 10.1016/s0026-0495(03)00055-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The current study aimed to compare the effects of treatment (2 months) with thiazolidinediones (TZDs) and placebo on glucose and fat metabolism in patients with type 2 diabetes (T2DM) in a crossover design. Eight patients received placebo (2 months) followed by TZD (2 months). Two-stage (1.5 and 6.0 pmol/kg min) hyperinsulinemic-euglycemic clamps were performed in all 8 patients pre- and post-placebo and post-TZD (post-placebo = pre-TZD). We determined rates of glucose disappearance (G(Rd)), glycolysis (GLS), glycogen synthesis (GS) (all with 3-(3)H glucose), carbohydrate (CHO) oxidation (indirect calorimetry), endogenous glucose production (EGP), free fatty acid (FFA) release ((2)H(5) glycerol), and oxidation (indirect calorimetry) and re-esterification, as well as plasma adiponectin and leptin concentrations, and fat cell size and number (determined in upper thigh biopsy samples). Placebo treatment had no effects on any of the measured parameters. TZD treatment improved insulin-stimulated glucose uptake (ISGU) from 17.1 to 26.4 micromol/kg min (P <.01) and insulin-stimulated GS from 4.8 to 13.4 micromol/kg min (P < 0.03), potentiated insulin-induced suppression of lipolysis from 4.3 to 2.3 micromol/kg min (P <.03) and FFA re-esterification from 1.9 to 1.0 micromol/kg min (P <.02), increased plasma adiponectin levels from 2.7 to 7.2 microg/mL (P <.05), and decreased plasma leptin levels from 30.8 to 23.4 ng/mL (P <.02). In addition, TZD tended to increase the number of small adipocytes (<50 microm) in subcutaneous adipose tissue. We conclude that TZDs have multiple actions and that many, but perhaps not all, can be accounted for by their action on adipose tissue.
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Affiliation(s)
- Guenther Boden
- Division of Endocrinology/Diabetes/Metabolism and the General Clinical Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
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13
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Meijssen S, Derksen RJ, Bilecen S, Erkelens DW, Cabezas MC. In vivo modulation of plasma free fatty acids in patients with familial combined hyperlipidemia using lipid-lowering medication. J Clin Endocrinol Metab 2002; 87:1576-80. [PMID: 11932285 DOI: 10.1210/jcem.87.4.8408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
One of the best studied aspects of the insulin resistance syndrome in familial combined hyperlipidemia (FCHL) is impaired insulin-mediated suppression of FFA by diminished inhibition of hormone-sensitive lipase (HSL). In vitro experiments have shown that stimulation of HSL activity by catecholamines is decreased in FCHL. The aim of this study was to investigate HSL inhibition by insulin and stimulation by endogenous catecholamines in vivo in FCHL patients. Twelve FCHL subjects using lipid-lowering medication and 12 controls underwent a mental stress test after random ingestion of either 50 g glucose or placebo. After ingestion of glucose, insulin concentrations increased from 76.8 +/- 21.5 pM to a maximum of 520.2 +/- 118.4 pM (P < 0.01) in FCHL and from 38.0 +/- 5.0 to 221.7 +/- 25.1 pM (P < 0.01) in controls. The percent decreases in plasma FFA during the first hour after glucose ingestion were similar in FCHL and controls (67 +/- 5% vs. 72 +/- 3%, respectively), suggesting a comparable inhibition of HSL in both. During the placebo test, FFA increased similarly in FCHL (56 +/- 9%) and controls (57 +/- 19%). In contrast, FFA concentrations did not change during mental stress after ingestion of glucose (from 0.17 +/- 0.02 to 0.15 +/- 0.02 mmol/liter in FCHL and from 0.11 +/- 0.02 to 0.12 +/- 0.02 mmol/liter in controls). In conclusion, the present study provides in vivo evidence for intact insulin-mediated suppression of FFA in FCHL, although this inhibition of HSL was achieved by higher insulin levels, suggesting insulin resistance at the level of HSL. Secondly, the induction of HSL activity by endogenous catecholamines in vivo is not decreased in FCHL, in contrast to earlier in vitro findings. Finally, catecholamine-induced HSL activation can be inhibited by insulin in a similar manner in both FCHL and controls.
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Affiliation(s)
- S Meijssen
- Department of Vascular Medicine, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands
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14
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Butte NF. Carbohydrate and lipid metabolism in pregnancy: normal compared with gestational diabetes mellitus. Am J Clin Nutr 2000; 71:1256S-61S. [PMID: 10799399 DOI: 10.1093/ajcn/71.5.1256s] [Citation(s) in RCA: 476] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This article reviews maternal metabolic strategies for accommodating fetal nutrient requirements in normal pregnancy and in gestational diabetes mellitus (GDM). Pregnancy is characterized by a progressive increase in nutrient-stimulated insulin responses despite an only minor deterioration in glucose tolerance, consistent with progressive insulin resistance. The hyperinsulinemic-euglycemic glucose clamp technique and intravenous-glucose-tolerance test have indicated that insulin action in late normal pregnancy is 50-70% lower than in nonpregnant women. Metabolic adaptations do not fully compensate in GDM and glucose intolerance ensues. GDM may reflect a predisposition to type 2 diabetes or may be an extreme manifestation of metabolic alterations that normally occur in pregnancy. In normal pregnant women, basal endogenous hepatic glucose production (R(a)) was shown to increase by 16-30% to meet the increasing needs of the placenta and fetus. Total gluconeogenesis is increased in late gestation, although the fractional contribution of total gluconeogenesis to R(a), quantified from (2)H enrichment on carbon 5 of glucose (65-85%), does not differ in pregnant women after a 16-h fast. Endogenous hepatic glucose production was shown to remain sensitive to increased insulin concentration in normal pregnancy (96% suppression), but is less sensitive in GDM (80%). Commensurate with the increased rate of glucose appearance, an increased contribution of carbohydrate to oxidative metabolism has been observed in late pregnancy compared with pregravid states. The 24-h respiratory quotient is significantly higher in late pregnancy than postpartum. Recent advances in carbohydrate metabolism during pregnancy suggest that preventive measures should be aimed at improving insulin sensitivity in women predisposed to GDM. Further research is needed to elucidate the mechanisms and consequences of alterations in lipid metabolism during pregnancy.
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Affiliation(s)
- N F Butte
- US Department of Agriculture, Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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15
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Albu JB, Curi M, Shur M, Murphy L, Matthews DE, Pi-Sunyer FX. Systemic resistance to the antilipolytic effect of insulin in black and white women with visceral obesity. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:E551-60. [PMID: 10484369 DOI: 10.1152/ajpendo.1999.277.3.e551] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was designed to determine the role of visceral adipose tissue (VAT) accumulation in systemic fat metabolism and to compare this in black and white women who differ in their manifestations of upper body obesity. Systemic glycerol and free fatty acid (FFA) turnover rates (rates of appearance, Ra) were measured in the basal state and during a pancreatic euglycemic clamp in nondiabetic, premenopausal, obese black and white women with a wide range of VAT accumulation. The slopes of the regression equations predicting basal and insulin-suppressed RaGlycerol and RaFFA from VAT area, age, and fat mass or fat-free mass did not significantly differ between black and white women. VAT area was the best predictor of the %-suppressed RaGlycerol and RaFFA during the pancreatic clamp (partial r = 0.76, P < 0.0001 and partial r = 0.60, P < 0.05, respectively). Basal R(a)Glycerol, but not RaFFA, was lower in black than in white women (P < 0.05). During the clamp, black women showed greater insulin suppression of RaGlycerol than of RaFFA (P < 0.0001) and greater insulin suppression of RaGlycerol (P < 0. 05) but similar suppression of RaFFA compared with white women. These differences were independent of age, fat mass, or fat-free mass and were partly explained by a lower VAT in black women. Thus, in both races, VAT accumulation was associated with systemic resistance to the antilipolytic effect of insulin and, in obese black women, systemic lipolysis measured as glycerol turnover rate was more responsive to insulin suppression than were systemic FFA turnover rates.
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Affiliation(s)
- J B Albu
- Columbia University, New York, New York 10025, USA.
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16
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Van Harmelen V, Reynisdottir S, Cianflone K, Degerman E, Hoffstedt J, Nilsell K, Sniderman A, Arner P. Mechanisms involved in the regulation of free fatty acid release from isolated human fat cells by acylation-stimulating protein and insulin. J Biol Chem 1999; 274:18243-51. [PMID: 10373426 DOI: 10.1074/jbc.274.26.18243] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The effects of acylation-stimulating protein (ASP) and insulin on free fatty acid (FFA) release from isolated human fat cells and the signal transduction pathways to induce these effects were studied. ASP and insulin inhibited basal and norepinephrine-induced FFA release by stimulating fractional FFA re-esterification (both to the same extent) and by inhibiting FFA produced during lipolysis (ASP to a lesser extent than insulin). Protein kinase C inhibition influenced none of the effects of ASP or insulin. Phosphatidylinositol 3-kinase inhibition counteracted the effects of insulin but not of ASP. Phosphodiesterase 3 (PDE3) activity was stimulated by ASP and insulin, whereas PDE4 activity was slightly increased by ASP only. Selective PDE3 inhibition reversed the effects of both ASP and insulin on fractional FFA re-esterification and lipolysis. Selective PDE4 inhibition slightly counteracted the ASP but not the effect of insulin on fractional FFA re-esterification and did not prevent the action of ASP or insulin on lipolysis. Thus, ASP and insulin play a major role in regulating FFA release from fat cells as follows: insulin by stimulating fractional FFA re-esterification and inhibiting lipolysis and ASP mainly by stimulating fractional FFA re-esterification. For both ASP and insulin these effects on FFA release are mediated by PDE3, and for ASP PDE4 might also be involved. The signaling pathway preceding PDE is not known for ASP but involves phosphatidylinositol 3-kinase for insulin.
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Affiliation(s)
- V Van Harmelen
- Department of Medicine and Research Center, Huddinge University Hospital, Karolinska Institute, S-141 86 Huddinge, Sweden
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17
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Lewis GF, Steiner G. Hypertriglyceridemia and its Metabolic Consequences as a Risk Factor for Atherosclerotic Cardiovascular Disease in Non-Insulin-Dependent Diabetes Mellitus. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1099-0895(199603)12:1<37::aid-dmr156>3.0.co;2-q] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Jensen MD. Regional glycerol and free fatty acid metabolism before and after meal ingestion. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:E863-9. [PMID: 10329980 DOI: 10.1152/ajpendo.1999.276.5.e863] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We measured splanchnic and leg glycerol [and free fatty acid (FFA)] uptake and release in 11 healthy volunteers before and after meal ingestion to assess whether regional FFA-to-glycerol release ratios mirror systemic release ratios. Basal splanchnic triglyceride release was also assessed. Although basal splanchnic glycerol uptake (111 +/- 18 micromol/min) accounted for most of systemic glycerol rate of appearance (156 +/- 20 micromol/min), leg glycerol uptake was also noted. The basal, systemic FFA-to-glycerol release ratio was less (2.6 +/- 0.2, P < 0.05) than the splanchnic ratio of 6.1 +/- 1.3, and the leg FFA-to-glycerol release ratio under fed conditions was less than the systemic ratio (0.9 +/- 0.1 vs. 1.6 +/- 0.2, respectively, P < 0.05). Basal splanchnic triglyceride production rates were 74 +/- 20 micromol/min, which could produce equimolar amounts of glycerol in the peripheral circulation via lipoprotein lipase action. In summary, 1) regional FFA-to-glycerol release ratios do not mirror systemic ratios, 2) leg glycerol uptake occurs in humans, and 3) splanchnic triglyceride production rates are substantial relative to systemic glycerol appearance. Glycerol appearance rates may not be a quantitative index of whole body lipolysis.
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Affiliation(s)
- M D Jensen
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA.
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19
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Lewis GF, Vranic M, Giacca A. Role of free fatty acids and glucagon in the peripheral effect of insulin on glucose production in humans. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:E177-86. [PMID: 9688888 DOI: 10.1152/ajpendo.1998.275.1.e177] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have shown previously that the greater suppression of endogenous glucose production (GP) with equimolar peripheral vs. portal insulin cannot be detected or is minimally reversed when the insulin-induced suppression of either free fatty acids (FFA) or glucagon alone is prevented. The present experiments were designed to minimize the insulin suppression of both glucagon and FFA in an attempt to further examine the mechanism of insulin's peripheral effect on GP. In nine healthy men, we investigated the effect of limiting the insulin suppression of both FFA and glucagon by infusing heparin (250 U/h), Intralipid 10% (25 ml/h), and glucagon (0.65 ng . kg-1 . min-1) during 1) portal (n = 9), 2) equimolar peripheral (n = 9), and 3) half-dose peripheral insulin delivery (n = 4) by use of our previously published tolbutamide infusion method, with calculation and matching of insulin secretion rate. GP decreased by 57.2 +/- 2. 6% with portal, 39.0 +/- 4.1% with equimolar peripheral, and 31.5 +/- 2.7% with half-dose peripheral insulin delivery (P < 0.001 for portal vs. peripheral and P < 0.001 for portal vs. half-dose peripheral). In contrast, in six control subjects in whom glucagon and FFA were not replaced, GP decreased by 62.6 +/- 2.4% with portal (n = 6), 75.7 +/- 3.0% with peripheral (n = 6), and 56.3 +/- 3.0% with half-dose peripheral (n = 4) insulin delivery (P < 0.01 for portal vs. peripheral and P = not significant for portal vs. half-dose peripheral). In summary, the greater suppression of GP with equimolar peripheral vs. portal insulin is eliminated and markedly reversed if the acute insulin-induced suppression of both plasma FFA and glucagon is minimized. This suggests that the insulin-induced suppression of glucagon and FFA has additive or cooperative effects in mediating the acute extrahepatic effect of insulin on GP.
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Affiliation(s)
- G F Lewis
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5G 2C4
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20
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Young MA, Eckland DJ, Eastmond R, Lettis S. Establishing the dose response curve for metabolic control with troglitazone, an insulin action enhancer, in type 2 diabetes patients. Ann Med 1998; 30:206-12. [PMID: 9667800 DOI: 10.3109/07853899808999405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Troglitazone is a novel once-daily oral antidiabetic agent for the treatment of type 2 diabetes patients. Here, we report the overall dose response characteristics of troglitazone, with respect to effects on metabolic control, using a pharmacodynamic model. Data from week 12 from two previously reported double-blind, randomized, parallel-group, placebo-controlled, dose-ranging multicentre studies examining once-daily doses of 10, 30, 100, 200, 400, 600 and 800 mg of troglitazone were combined for the analyses. The pharmacodynamic relationships for relevant parameters of metabolic control were modelled using a nonlinear regression modelling programme. The troglitazone dose-concentration relationship was linear over 10-800 mg. Using an inhibitory sigmoid Emax model, ED50 values of approximately 100 mg and 200 mg were found for fasting serum glucose and triglycerides, respectively. The 200 mg dose for HbA1c showed an inconsistent reduction compared with placebo between the two studies; this illustrates the difficulties associated with comparing results from different assay techniques. Insulin and nonesterified fatty acid reductions compared with placebo were not consistent between studies, and no pharmacodynamic modelling was possible. No changes in body weight were observed at any dose. Troglitazone was as well tolerated as placebo across the dose range investigated. This pharmacodynamic analysis has established that 200-600 mg once daily can be considered the therapeutic dose range of troglitazone that significantly improves metabolic control in type 2 diabetes patients.
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Affiliation(s)
- M A Young
- Department of Clinical Pharmacokinetics and Dynamics, Glaxo Wellcome Research and Development Ltd, Greenford, Middlesex, UK.
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21
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Robinson C, Tamborlane WV, Maggs DG, Enoksson S, Sherwin RS, Silver D, Shulman GI, Caprio S. Effect of insulin on glycerol production in obese adolescents. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:E737-43. [PMID: 9575836 DOI: 10.1152/ajpendo.1998.274.4.e737] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Impaired stimulation of glucose metabolism and reduced suppression of lipolytic activity have both been suggested as important defects related to the insulin resistance of adolescent obesity. To further explore the relationship between these abnormalities, we studied seven obese [body mass index (BMI) 35 +/- 2 kg/m2] and seven lean (BMI 21 +/- 1 kg/m2) adolescents aged 13-15 yr and compared them with nine lean adults (aged 21-27 yr, BMI 23 +/- 1 kg/m2) during a two-step euglycemic-hyperinsulinemic clamp in combination with 1) a constant [2H5]glycerol (1.2 mg.m-2.min-1) infusion to quantify glycerol turnover and 2) indirect calorimetry to estimate glucose and net lipid oxidation rates. In absolute terms, basal glycerol turnover was increased and suppression by insulin was impaired in obese adolescents compared with both groups of lean subjects (P < 0.01). However, when the rates of glycerol turnover were adjusted for differences in body fat mass, the rates were similar in all three groups. Basal plasma free fatty acid (FFA) concentrations were significantly elevated, and the suppression by physiological increments in plasma insulin was impaired in obese adolescents compared with lean adults (P < 0.05). In parallel with the high circulating FFA levels, net lipid oxidation in the basal state and during the clamp was also elevated in the obese group compared with lean adults. Net lipid oxidation was inversely correlated with glucose oxidation (r = -0.50, P < 0.01). In conclusion, these data suggest that lipolysis is increased in obese adolescents (vs. lean adolescents and adults) as a consequence of an enlarged adipose mass rather than altered sensitivity of adipocytes to the suppressing action of insulin.
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Affiliation(s)
- C Robinson
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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22
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Hsu HW, Butte NF, Wong WW, Moon JK, Ellis KJ, Klein PD, Moise KJ. Oxidative metabolism in insulin-treated gestational diabetes mellitus. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 272:E1099-107. [PMID: 9227457 DOI: 10.1152/ajpendo.1997.272.6.e1099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To investigate whether protein, carbohydrate, and fat metabolism was normalized in insulin-treated gestational diabetes mellitus (GDM), eight Hispanic women with GDM and eight healthy controls were studied at 32-36 wk of gestation and 6 wk postpartum. Net substrate utilization was measured using room respiration calorimetry. Exogenous substrate oxidation was determined by 13C recovered in breath CO2 from 13C-labeled leucine, glucose, and Hiolein. Women with GDM had higher 24-h oxygen consumption, carbon dioxide production, total energy expenditure, and basal metabolic rates than controls due to larger body mass. Adjusted for weight or fat-free mass, total energy expenditure, basal metabolic rate, and basal and 24-h whole body net protein, carbohydrate, and fat utilization did not differ between insulin-treated GDM subjects and controls in pregnancy or postpartum. Oxidation of [13C]leucine and [13C]glucose did not differ by group or pregnancy status. Recovery of exogenously administered [13C]Hiolein, a biosynthetic triglyceride, as breath 13CO2 was significantly lower in the GDM group antepartum and postpartum (P = 0.02), indicating lower oxidation of exogenous triglycerides in GDM.
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Affiliation(s)
- H W Hsu
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas 77030, USA
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23
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Sumner AE, Kushner H, Tulenko TN, Falkner B, Marsh JB. The relationship in African-Americans of sex differences in insulin-mediated suppression of nonesterified fatty acids to sex differences in fasting triglyceride levels. Metabolism 1997; 46:400-5. [PMID: 9109843 DOI: 10.1016/s0026-0495(97)90055-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Insulin is a potent antilipolytic hormone that promotes the deposition of fat and decreases the release of nonesterified fatty acids (NEFA) from adipose tissue. The purpose of this study was to investigate in African-Americans (AAs) sex differences in insulin-mediated suppression of plasma NEFA and fasting triglyceride (TG) levels. Ninety AAs, 44 men and 46 women with a mean age of 34 +/- 8 years were classified by body mass index (BMI) into three groups: non-obese (22 men and 18 women), obese (12 men and 10 women), and severely obese (10 men and 18 women). In each BMI group, women versus men had greater percent body fat (non-obese, 30 +/- 6 v 18 +/- 6, P < .001; obese, 36 +/- 3 v 26 +/- 2, P < .001; and severely obese, 39 +/- 4 v 29 +/- 4, P < .001). An oral glucose tolerance test (OGTT) was performed with fasting TG levels and plasma insulin and NEFA concentrations obtained at 0, 30, 60, and 120 minutes. In women, insulin-mediated NEFA suppression was similar in each of the three BMI groups (non-obese, 85% +/- 14%; obese, 88% +/- 11%; and severely obese, 87% +/- 10%; P = .8). In men, the percent suppression of NEFA declined with increasing obesity (non-obese, 83% +/- 14%; obese, 71% +/- 21%; and severely obese, 68% +/- 16%; P = .04). Changes in NEFA suppression were reflected in the fasting TG levels. TG levels in women were similar in each BMI group (non-obese, 71 +/- 39 mg/dL; obese; 69 +/- 21; severely obese, 79 +/- 30; P = .7). In contrast, fasting TG levels for men were higher in the higher BMI groups. Plasma TG levels in men were 87 +/- 41 mg/dL for obese, 113 +/- 65 for obese, and 169 +/- 81 for severely obese (P = .001). These data demonstrate sex differences in insulin-mediated NEFA metabolism. In AA women, the maintenance of sensitivity to insulin-mediated suppression of NEFA regardless of the degree of obesity may contribute to the normal plasma TG levels. For AA men, the resistance to insulin-mediated suppression of NEFA in the higher BMI categories may allow more NEFA to be released from adipose tissue into the circulation and available to the liver for synthesis into TG-containing lipoproteins.
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Affiliation(s)
- A E Sumner
- Institute for Women's Health, Allegheny University of the Health Sciences, Philadelphia, PA 19129, USA
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24
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Sumner AE, Kushner H, Lakota CA, Falkner B, Marsh JB. Gender differences in insulin-induced free fatty acid suppression: studies in an African American population. Lipids 1996; 31 Suppl:S275-8. [PMID: 8729133 DOI: 10.1007/bf02637090] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This study of African Americans (AA) was designed to investigate gender differences in insulin-induced free fatty acid (FFA) suppression. Sixty AA (34 women, mean age 34 +/- 7.6 years, and 26 men, mean age 30 +/- 2.9 years) participated. All subjects had an oral glucose tolerance test (OGTT). Nineteen women and 18 men also underwent a euglycemic hyperinsulinemic clamp (IC) study. Plasma insulin and FFA concentrations were obtained during both tests at 0, 60, and 120 min. While there was no gender difference in body mass index (P = 0.21), women had greater percent body fat (P < 0.001) calculated by the Siri formula. There was no gender difference in fasting FFA levels, but during the OGTT, women compared to men had significantly greater FFA suppression. Both nonobese and obese women suppressed FFA concentration by 88%, and nonobese and obese men suppressed FFA concentration by 80 and 66% respectively. This gender difference in FFA suppression was significant (P = 0.001) and independent of obesity and insulin concentration. During the IC studies, there were no gender or obesity differences in FFA suppression, with women and men suppressing FFA levels by 87-89% (P = 0.7). Fasting insulin concentrations were higher in obese vs. nonobese (P = 0.03), but fasting FFA concentrations were not different (P = 0.15). For nonobese and obese females, fasting FFA levels were 0.55 +/- 0.24 and 0.44 +/- 0.26 mEq/L, respectively, and for nonobese and obese males, 0.45 +/- 0.2 and 0.35 +/- 0.18 mEq/L, respectively. In women, development of obesity may be enhanced by greater sensitivity to insulin-induced FFA suppression as measured during an OGTT. To detect gender differences in FFA metabolism, the OGTT is superior to the IC. The lack of elevation in fasting FFA levels in obese AA women and men has not been reported in other racial groups and may indicate a greater adipocyte sensitivity to insulin in AA.
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Affiliation(s)
- A E Sumner
- Medical College of Pennsylvania, Philadelphia, USA
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25
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Binnert C, Laville M, Pachiaudi C, Rigalleau V, Beylot M. Use of gas chromatography/isotope ratio-mass spectrometry to study triglyceride metabolism in humans. Lipids 1995; 30:869-73. [PMID: 8577232 DOI: 10.1007/bf02533964] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The study of triglyceride (TG) metabolism using stable isotope tracers would be facilitated by being able to detect low 13C enrichment. To meet this goal, we developed a gas chromatography/isotope ratio-mass spectrometry technique to measure the enrichment of palmitate in nonesterified fatty acids (NEFA) and TG as its methyl derivative. This method allows accurate and reproducible measurements of enrichment as low as 0.009 mole percent excess (MPE), in a range between 0-0.65 MPE. The usefulness of this method is shown by two studies of lipid metabolism in human beings. First, we studied the metabolic fate of an oral TG load labeled with [1,1,1-13C3]tripalmitin. Labeled palmitate appeared concurrently in plasma NEFA and TG, and four hours after the load, the labeling was higher in NEFA than in TG (MPE NEFA: 1.53 +/- 0.31 vs. MPE TG: 0.78 +/- 0.06, P < 0.05). In a second study, the hepatic reesterification of NEFA was estimated by measuring the appearance of infused [1-13C]palmitate in circulating TG. The estimated contribution of plasma NEFA to circulating TG increased to a maximum of 22%. Thus, gas chromatography/isotope ratio-mass spectrometry appears to be a useful tool for future studies of lipid metabolism in humans.
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Affiliation(s)
- C Binnert
- INSERM U 197, Faculté de Médecine Alexis Carrel, Lyon, France
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