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Brockman NK, Yardley JE. Sex-related differences in fuel utilization and hormonal response to exercise: implications for individuals with type 1 diabetes. Appl Physiol Nutr Metab 2018; 43:541-552. [PMID: 29420905 DOI: 10.1139/apnm-2017-0559] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sex-related differences in metabolic and neuroendocrine response to exercise in individuals without diabetes have been well established. Men and women differ in fuel selection during exercise, in which women rely to a greater extent on fat oxidation, whereas males rely mostly on carbohydrate oxidation for energy production. The difference in fuel selection appears to be mediated by sex-related differences in hormonal (including catecholamines, growth hormone, and estrogen) response to different types and intensities of exercise. In general, men exhibit an amplified counter-regulatory response to exercise, with elevated levels of catecholamines compared with women. However, women exhibit greater sensitivity to the lipolytic action of the catecholamines and deplete less of their glycogen stores than men during exercise, which suggests that women may experience a greater defense in blood glucose control after exercise than men. Conversely, little is known about sex-related differences in response to exercise in individuals with type 1 diabetes (T1D). A single study investigating sex-related differences in response to moderate aerobic exercise in individuals with T1D found sex-related differences in catecholamine response and fuel selection, but changes in blood glucose were not measured. To our knowledge, there are no studies investigating sex-related differences in blood glucose responses to different types and intensities of exercise in individuals with T1D. This review summarizes sex-related differences in exercise responses that could potentially impact blood glucose levels during exercise in individuals with T1D and highlights the need for further research.
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Affiliation(s)
- Nicole K Brockman
- a Augustana Faculty, University of Alberta, 4901-46th Avenue, Camrose, AB T4V 2R3, Canada
| | - Jane E Yardley
- a Augustana Faculty, University of Alberta, 4901-46th Avenue, Camrose, AB T4V 2R3, Canada.,b Physical Activity and Diabetes Laboratory, Alberta Diabetes Institute, 8602-112 Street, Edmonton, AB T6G 2E1, Canada
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2
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Grayson BE, Gutierrez-Aguilar R, Sorrell JE, Matter EK, Adams MR, Howles P, Karns R, Seeley RJ, Sandoval DA. Bariatric surgery emphasizes biological sex differences in rodent hepatic lipid handling. Biol Sex Differ 2017; 8:4. [PMID: 28149499 PMCID: PMC5273842 DOI: 10.1186/s13293-017-0126-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/18/2017] [Indexed: 12/15/2022] Open
Abstract
Background Eighty percent of patients who receive bariatric surgery are women, yet the majority of preclinical studies are in male rodents. Because sex differences drive hepatic gene expression and overall lipid metabolism, we sought to determine whether sex differences were also apparent in these endpoints in response to bariatric surgery. Methods Two cohorts of age-matched virgin male and female Long-Evans rats were placed on a high fat diet for 3 weeks and then received either Sham or vertical sleeve gastrectomy (VSG), a surgery which resects 80% of the stomach with no intestinal rearrangement. Results Each sex exhibited significantly decreased body weight due to a reduction in fat mass relative to Sham controls (p < 0.05). Microarray and follow-up qPCR on liver revealed striking sex differences in gene expression after VSG that reflected a down-regulation of hepatic lipid metabolism and an up-regulation of hepatic inflammatory pathways in females vs. males after VSG. While the males had a significant reduction in hepatic lipids after VSG, there was no reduction in females. Ad lib-fed and fasting circulating triglycerides, and postprandial chylomicron production were significantly lower in VSG relative to Sham animals of both sexes (p < 0.01). However, hepatic VLDL production, highest in sham-operated females, was significantly reduced by VSG in females but not males. Conclusions Taken together, although both males and females lose weight and improve plasma lipids, there are large-scale sex differences in hepatic gene expression and consequently hepatic lipid metabolism after VSG. Electronic supplementary material The online version of this article (doi:10.1186/s13293-017-0126-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bernadette E Grayson
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS USA
| | - Ruth Gutierrez-Aguilar
- Divsion de Investigacion, Facultad de Medicina, Universidad Nacional Autónoma de México and Laboratorio de Enfermedades Metabólicas Obesidad y Diabetes, Hospital Infantil de México "Federico Gómez", Mexico, Mexico
| | - Joyce E Sorrell
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio USA
| | - Emily K Matter
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio USA
| | - Michelle R Adams
- Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio USA
| | - Philip Howles
- Department of Pathology, University of Cincinnati, Cincinnati, Ohio USA
| | - Rebekah Karns
- Bioinformatics Core, Cincinnati Children's Hospital and Medical Center, Cincinnati, Ohio USA
| | - Randy J Seeley
- Department of Surgery, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 USA
| | - Darleen A Sandoval
- Department of Surgery, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109 USA
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3
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Lundsgaard AM, Kiens B. Gender differences in skeletal muscle substrate metabolism - molecular mechanisms and insulin sensitivity. Front Endocrinol (Lausanne) 2014; 5:195. [PMID: 25431568 PMCID: PMC4230199 DOI: 10.3389/fendo.2014.00195] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 10/30/2014] [Indexed: 12/23/2022] Open
Abstract
It has become increasingly apparent that substrate metabolism is subject to gender-specific regulation, and the aim of this review is to outline the available evidence of molecular gender differences in glucose and lipid metabolism of skeletal muscle. Female sex has been suggested to have a favorable effect on glucose homeostasis, and the available evidence from hyperinsulinemic-euglycemic clamp studies is summarized to delineate whether there is a gender difference in whole-body insulin sensitivity and in particular insulin-stimulated glucose uptake of skeletal muscle. Whether an eventual higher insulin sensitivity of female skeletal muscle can be related to gender-specific regulation of molecular metabolism will be topic for discussion. Gender differences in muscle fiber type distribution and substrate availability to and in skeletal muscle are highly relevant for substrate metabolism in men and women. In particular, the molecular machinery for glucose and fatty acid oxidative and storage capacities in skeletal muscle and its implications for substrate utilization during metabolic situations of daily living are discussed, emphasizing their relevance for substrate choice in the fed and fasted state, and during periods of physical activity and recovery. Together, handling of carbohydrate and lipids and regulation of their utilization in skeletal muscle have implications for whole-body glucose homeostasis in men and women. 17-β estradiol is the most important female sex hormone, and the identification of estradiol receptors in skeletal muscle has opened for a role in regulation of substrate metabolism. Also, higher levels of circulating adipokines as adiponectin and leptin in women and their implications for muscle metabolism will be considered.
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Affiliation(s)
- Anne-Marie Lundsgaard
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Bente Kiens, Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Universitetsparken 13, Copenhagen 2100, Denmark e-mail:
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Hagobian TA, Yamashiro M, Hinkel-Lipsker J, Streder K, Evero N, Hackney T. Effects of acute exercise on appetite hormones and ad libitum energy intake in men and women. Appl Physiol Nutr Metab 2013; 38:66-72. [DOI: 10.1139/apnm-2012-0104] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Acute exercise suppresses relative energy intake; however, it remains unclear whether this occurs in both men and women exposed to the same relative exercise treatment. Eleven healthy men (22 ± 2 years; 16% ± 6% body fat (BF); 26 ± 4 body mass index (BMI); 42.9 ± 6.5 mL·kg–1·min–1 peak oxygen consumption ([Formula: see text]O2peak)) and 10 healthy women (21 ± 2 years; 24 ± 2 BMI; 23% ± 3% BF; 39.9 ± 5.5 mL·kg–1·min–1 [Formula: see text]O2peak) rested for 60 min or exercised on a cycle ergometer at 70% [Formula: see text]O2peak until 30% of total daily energy expenditure was expended (men, expenditure = 975 ± 195 kcal in 82 ± 13 min; women, expenditure = 713 ± 86 kcal in 84 ± 17 min) in a counterbalanced, crossover fashion. Appetite hormones and appetite ratings were assessed in response to each condition. Forty minutes after both conditions, ad libitum total and relative energy intake (energy intake minus energy cost of exercise) were assessed at a buffet meal. There was no significant sex or condition effect in appetite hormones (PYY3-36, acylated ghrelin, insulin) and appetite ratings (hunger, satisfaction, fullness). Total energy intake in men was significantly higher (P < 0.05) in exercise and rest conditions (1648 ± 950, 1216 ± 633 kcal, respectively) compared with women (591 ± 183, 590 ± 231 kcal, respectively). Relative energy intake was significantly lower (P < 0.05) after exercise compared with rest in men (672 ± 827, 1133 ± 619 kcal, respectively) and women (−121 ± 243, 530 ± 233 kcal, respectively). These data highlight the effectiveness of acute exercise to suppress relative energy intake regardless of sex.
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Affiliation(s)
- Todd Alan Hagobian
- Kinesiology Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Megan Yamashiro
- Kinesiology Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Jake Hinkel-Lipsker
- Kinesiology Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Katherine Streder
- Kinesiology Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Nero Evero
- Kinesiology Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Terry Hackney
- Kinesiology Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
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5
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Does insulin resistance drive the association between hyperglycemia and cardiovascular risk? PLoS One 2012; 7:e39260. [PMID: 22720085 PMCID: PMC3376119 DOI: 10.1371/journal.pone.0039260] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 05/22/2012] [Indexed: 12/14/2022] Open
Abstract
Background Several studies have shown associations between hyperglycemia and risk of cardiovascular disease (CVD) and mortality, yet glucose-lowering treatment does little to mitigate this risk. We examined whether associations between hyperglycemia and CVD risk were explained by underlying insulin resistance. Methods In 60 middle-aged individuals without diabetes we studied the associations of fasting plasma glucose, 2-hour post oral glucose tolerance test plasma glucose, insulin sensitivity as well as body fat percentage with CVD risk. Insulin sensitivity was measured as the glucose infusion rate during a euglycemic hyperinsulinemic clamp, body fat percentage was measured by dual X-ray absorptiometry, and CVD risk was estimated using the Framingham risk score. Associations of fasting plasma glucose, 2-hour plasma glucose, insulin sensitivity and body fat percentage with the Framingham risk score were assessed in linear regression models. Results Both fasting and 2-hour plasma glucose levels were associated with higher Framingham risk score (fasting glucose: r2 = 0.21; 2-hour glucose: r2 = 0.24; P<0.001 for both), and insulin sensitivity with lower Framingham risk score (r2 = 0.36; P<0.001). However, adjustment for insulin sensitivity and 2-hour glucose made the effect of fasting glucose non-significant (P = 0.060). Likewise, when adjusting for insulin sensitivity and fasting glucose, the association between 2-hour glucose and Framingham risk score disappeared (P = 0.143). In contrast, insulin sensitivity was still associated with Framingham risk score after adjusting for glucose levels (P<0.001). Body fat was not associated with Framingham risk score when taking insulin sensitivity into account (P = 0.550). Conclusion The association between plasma glucose levels and CVD risk is mainly explained by insulin resistance, which raises the question of whether glucose lowering per se without changes in the processes that underlie hyperglycemia should be the sole clinical paradigm in the treatment of type 2 diabetes or its prevention.
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Perreault L, Bergman BC, Hunerdosse DM, Eckel RH. Altered intramuscular lipid metabolism relates to diminished insulin action in men, but not women, in progression to diabetes. Obesity (Silver Spring) 2010; 18:2093-100. [PMID: 20379150 PMCID: PMC3230250 DOI: 10.1038/oby.2010.76] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Whether sex differences in intramuscular triglyceride (IMTG) metabolism underlie sex differences in the progression to diabetes are unknown. Therefore, the current study examined IMTG concentration and fractional synthesis rate (FSR) in obese men and women with normal glucose tolerance (NGT) vs. those with prediabetes (PD). PD (n = 13 men and 7 women) and NGT (n = 7 men and 12 women) groups were matched for age and anthropometry. Insulin action was quantified using a hyperinsulinemic-euglycemic clamp with infusion of [6,6-(2)H(2)]-glucose. IMTG concentration was measured by gas chromatography/mass spectrometry (GC/MS) and FSR by GC/combustion isotope ratio MS (C-IRMS), from muscle biopsies taken after infusion of [U-(13)C]palmitate during 4 h of rest. In PD men, the metabolic clearance rate (MCR) of glucose was lower during the clamp (4.71 ± 0.77 vs. 8.62 ± 1.26 ml/kg fat-free mass (FFM)/min, P = 0.04; with a trend for lower glucose rate of disappearance (Rd), P = 0.07), in addition to higher IMTG concentration (41.2 ± 5.0 vs. 21.2 ± 3.4 µg/mg dry weight, P ≤ 0.01), lower FSR (0.21 ± 0.03 vs. 0.42 ± 0.06 %/h, P ≤ 0.01), and lower oxidative capacity (P = 0.03) compared to NGT men. In contrast, no difference in Rd, IMTG concentration, or FSR was seen in PD vs. NGT women. Surprisingly, glucose Rd during the clamp was not different between NGT men and women (P = 0.25) despite IMTG concentration being higher (42.6 ± 6.1 vs. 21.2 ± 3.4 µg/mg dry weight, P = 0.03) and FSR being lower (0.23 ± 0.04 vs. 0.42 ± 0.06 %/h, P = 0.02) in women. Alterations in IMTG metabolism relate to diminished insulin action in men, but not women, in the progression toward diabetes.
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Affiliation(s)
- Leigh Perreault
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Denver School of Medicine, Aurora, Colorado, USA.
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7
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Loizzo S, Vella S, Loizzo A, Fortuna A, Di Biase A, Salvati S, Frajese GV, Agrapart V, Ramirez Morales R, Spampinato S, Campana G, Capasso A, Galietta G, Guarino I, Carta S, Carru C, Zinellu A, Ghirlanda G, Seghieri G, Renzi P, Franconi F. Sexual dimorphic evolution of metabolic programming in non-genetic non-alimentary mild metabolic syndrome model in mice depends on feed-back mechanisms integrity for pro-opiomelanocortin-derived endogenous substances. Peptides 2010; 31:1598-605. [PMID: 20493223 DOI: 10.1016/j.peptides.2010.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 05/12/2010] [Accepted: 05/12/2010] [Indexed: 01/05/2023]
Abstract
Previously, we showed that our post-natal handling model induces pro-opiomelanocortin-derived (POMC) endogenous systems alterations in male mice at weaning. These alterations last up to adult age, and are at the basis of adult hormonal and metabolic conditions similar to mild metabolic syndrome/type-2 diabetes. Here, we evaluate how sex influences post-natal programming in these metabolic conditions. Subjects are adult control (non-handled) female (NHF) and male (NHM) CD-1 mice; adult post-natal handled female (HF) and male (HM) mice. Handling consists of daily maternal separation (10 min) plus sham injection, from birth to weaning (21 days). In adult handled males (90-days old) we find not only POMC-derived hormones alterations (enhanced basal plasma corticosterone (+91%) and ACTH (+109%)) but also overweight (+5.4%), fasting hyperglycemia (+40%), hypertriglyceridemia (+21%), enhanced brain mRNA expression of hydroxysteroid(11-beta)dehydrogenase type-1 (HSD11B1) (+49%), and decreased mRNA-HSD11B2 (-39%). Conversely, uric acid, creatinine, HDL(C), total cholesterol, glucose and insulin incremental area under-the-curve are not affected. In females, post-natal handling does not produce both hormonal and dysmetabolic diabetes-like changes; but handling enhances n3- and n6-poly-unsaturated, and decreases saturated fatty acids content in erythrocyte membrane composition in HF versus NHF. In conclusion, for the first time we show that female sex in mice exerts effective protection against the hypothalamus-pituitary-adrenal homeostasis disruption induced by our post-natal handling model on POMC cleavage products; endocrine disruption is in turn responsible for altered metabolic programming in male mice. The role of sex hormones is still to be elucidated.
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MESH Headings
- 11-beta-Hydroxysteroid Dehydrogenase Type 1/genetics
- 11-beta-Hydroxysteroid Dehydrogenase Type 1/metabolism
- 11-beta-Hydroxysteroid Dehydrogenase Type 2/genetics
- 11-beta-Hydroxysteroid Dehydrogenase Type 2/metabolism
- Adrenocorticotropic Hormone/blood
- Animals
- Animals, Newborn
- Brain/metabolism
- Corticosterone/blood
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/metabolism
- Feedback, Physiological
- Female
- Gene Expression Regulation, Enzymologic
- Handling, Psychological
- Hypothalamo-Hypophyseal System/metabolism
- Hypothalamo-Hypophyseal System/physiopathology
- Lipid Metabolism/physiology
- Male
- Metabolic Syndrome/blood
- Metabolic Syndrome/etiology
- Metabolic Syndrome/metabolism
- Metabolic Syndrome/physiopathology
- Mice
- Pain Threshold/physiology
- Pituitary-Adrenal System/metabolism
- Pituitary-Adrenal System/physiopathology
- Pro-Opiomelanocortin/metabolism
- RNA, Messenger/metabolism
- Random Allocation
- Sex Characteristics
- Stress, Psychological/complications
- Stress, Psychological/physiopathology
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Affiliation(s)
- Stefano Loizzo
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, via Regina Elena 299, 00161 Roma, Italy.
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8
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Magkos F, Wang X, Mittendorfer B. Metabolic actions of insulin in men and women. Nutrition 2010; 26:686-93. [PMID: 20392600 DOI: 10.1016/j.nut.2009.10.013] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Accepted: 10/24/2009] [Indexed: 12/31/2022]
Abstract
Insulin is an important regulator of glucose, lipid, and protein metabolism. It suppresses hepatic glucose and triglyceride production, inhibits adipose tissue lipolysis and whole-body and muscle proteolysis, and stimulates glucose uptake in muscle. In this review we discuss what is currently known about the control of substrate metabolism by insulin in men and women. The data available so far indicate that women are more sensitive to insulin with regards to glucose metabolism (both in the liver and in muscle), whereas there are no differences between men and women in insulin action on lipolysis. Potential differences exist in the regulation of plasma triglyceride concentration and protein metabolism by insulin and in changes in insulin action in response to stimuli (e.g., weight loss and exercise) that are known to alter insulin sensitivity. However, these areas have not been studied comprehensively enough to draw firm conclusions.
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Affiliation(s)
- Faidon Magkos
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
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9
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Magkos F, Patterson BW, Mohammed BS, Mittendorfer B. Basal adipose tissue and hepatic lipid kinetics are not affected by a single exercise bout of moderate duration and intensity in sedentary women. Clin Sci (Lond) 2009; 116:327-34. [PMID: 18752466 PMCID: PMC2626641 DOI: 10.1042/cs20080220] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hypertriacylglycerolaemia is an important risk factor for cardiovascular disease. In men, we have shown that the effects of evening exercise on basal VLDL (very-low-density lipoprotein) metabolism are dose-dependent: a single prolonged bout of aerobic exercise [2 h at 60% of VO(2 peak) (peak oxygen consumption)] reduces fasting plasma TAG [triacylglycerol (triglyceride)] concentrations, via enhanced clearance of VLDL-TAG from the circulation, whereas the same exercise performed for 1 h has no effect on VLDL-TAG metabolism and concentration. We hypothesized that women are more sensitive to the TAG-lowering effect of exercise because they reportedly use more intramuscular TAG as an energy source during exercise, and depletion of muscle TAG stores has been linked to reciprocal changes in skeletal muscle LPL (lipoprotein lipase) activity. To test our hypothesis, we measured basal VLDL-TAG and VLDL-apoB-100 (apolipoprotein B-100), and plasma NEFA [non-esterified fatty acid ('free fatty acid')] kinetics, by using stable isotope-labelled tracer techniques, on the morning after a single session of evening exercise of moderate duration and intensity (1 h at 60% of VO(2 peak)) in eight sedentary pre-menopausal women (age, 28+/-3 years; body mass index, 27+/-2 kg/m(2); body fat, 34+/-3%; values are means+/-S.E.M.). Compared with an equivalent period of evening rest, exercise had no effect on post-absorptive NEFA concentrations and the rate of appearance in plasma, VLDL-TAG and VLDL-apoB-100 concentrations, hepatic VLDL-TAG and VLDL-apoB-100 secretion and plasma clearance rates (all P>0.05). We conclude that, in women, as in men, a single session of exercise of moderate intensity and duration is not sufficient to bring about the alterations in VLDL metabolism that have been linked to post-exercise hypotriacylglycerolaemia.
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Affiliation(s)
- Faidon Magkos
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
- Department of Nutrition and Dietetics, Harokopio University, Athens, Greece
| | - Bruce W. Patterson
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - B. Selma Mohammed
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
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10
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Perreault L, Bergman BC, Playdon MC, Dalla Man C, Cobelli C, Eckel RH. Impaired fasting glucose with or without impaired glucose tolerance: progressive or parallel states of prediabetes? Am J Physiol Endocrinol Metab 2008; 295:E428-35. [PMID: 18523123 PMCID: PMC2519761 DOI: 10.1152/ajpendo.90354.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Our objective was to determine whether defects underlying impaired fasting glucose (IFG) are maintained and additive when combined with impaired glucose tolerance (IGT) (representing a progressive form of prediabetes) or are distinct in IFG/IGT (reflecting a parallel form of prediabetes). Volunteers with IFG (n = 10), IFG/IGT (n = 14), or normal glucose tolerance (NGT; n = 15) were matched for demographics and anthropometry. Insulin secretion was assessed using the glucose step-up protocol and insulin action through the use of a two-stage hyperinsulinemic euglycemic clamp with infusion of [6,6-(2)H(2)]glucose. Modeling of insulin secretory parameters revealed similar basal (Phi(b)) but diminished dynamic (Phi(d)) components in both IFG and IFG/IGT (P = 0.05 vs. NGT for both). Basal glucose rate of appearance (R(a)) was higher in IFG compared with NGT (P < 0.01) and also, surprisingly, with IFG/IGT (P < 0.04). Moreover, glucose R(a) suppressed more during the low-dose insulin clamp in IFG (P < 0.01 vs. NGT, P = 0.08 vs. IFG/IGT). Insulin-stimulated glucose uptake [glucose rate of disappearance (R(d))] was similar in IFG, IFG/IGT, and NGT throughout the clamp. We conclude that nuances of beta-cell dysfunction observed in IFG were also noted in IFG/IGT. A trend for additional insulin secretory defects was observed in IFG/IGT, possibly suggesting progression in beta-cell failure in this group. In contrast, basal glucose R(a) and its suppressability with insulin were higher in IFG, but not IFG/IGT, compared with NGT. Together, these data indicate that IFG/IGT may be a distinct prediabetic syndrome rather than progression from IFG.
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Affiliation(s)
- Leigh Perreault
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Health Sciences Center, Aurora, CO 80045, USA.
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11
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Paravidino AB, Portella ES, Soares EDA. Metabolismo energético em atletas de endurance é diferente entre os sexos. REV NUTR 2007. [DOI: 10.1590/s1415-52732007000300010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Atletas de endurance têm suas necessidades energéticas aumentadas devido ao seu alto gasto energético durante o exercício. Contudo, ainda não estão claros quais são as diferenças do metabolismo energético entre os sexos e se essas diferenças vão implicar em mudanças em suas dietas. Sendo assim, o objetivo deste trabalho foi reunir informações da literatura sobre as diferenças entre os sexos em relação ao metabolismo energético em atletas de endurance. Alguns estudos demonstram que, durante exercício de longa duração, as mulheres utilizam como fonte de energia maior quantidade de lipídeos e menor de carboidratos e proteínas, quando comparadas aos homens. Já outros autores não encontraram diferença entre os sexos na proporção dos substratos metabolizados, mas sim nos tipos de lipídeos utilizados. Essa diferença na utilização de substratos vem sendo relacionada a distintas concentrações de alguns hormônios entre homens e mulheres, como: 17beta-estradiol, progesterona, testosterona, epinefrina, norepinefrina, hormônio de crescimento, insulina e glucagon. Também foi observado que os atletas aumentam seus estoques de glicogênio quando consomem dieta com sobrecarga glicídica, enquanto que as atletas apenas têm seus estoques de glicogênio aumentados quando ingerem dieta com sobrecarga glicídica e hiperenergética. Esse achado é bastante relevante, pois a concentração de glicogênio está diretamente ligada ao rendimento do atleta durante o exercício de endurance. Portanto, a literatura sugere que há diferenças entre os sexos quanto à utilização de substratos em atletas. Porém, novos estudos são necessários para melhor esclarecimento do metabolismo energético dos atletas de endurance possibilitando, assim, a adequação de suas recomendações nutricionais.
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12
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Roepstorff C, Donsmark M, Thiele M, Vistisen B, Stewart G, Vissing K, Schjerling P, Hardie DG, Galbo H, Kiens B. Sex differences in hormone-sensitive lipase expression, activity, and phosphorylation in skeletal muscle at rest and during exercise. Am J Physiol Endocrinol Metab 2006; 291:E1106-14. [PMID: 16822962 DOI: 10.1152/ajpendo.00097.2006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Women have been shown to use more intramuscular triacylglycerol (IMTG) during exercise than men. To investigate whether this could be due to sex-specific regulation of hormone-sensitive lipase (HSL) and to use sex comparison as a model to gain further insight into HSL regulation, nine women and eight men performed bicycle exercise (90 min, 60% Vo(2peak)), and skeletal muscle HSL expression, phosphorylation, and activity were determined. Supporting previous findings, basal IMTG content (P < 0.001) and net IMTG decrease during exercise (P < 0.01) were higher in women than in men and correlated significantly (r = 0.72, P = 0.001). Muscle HSL mRNA (80%, P = 0.11) and protein content (50%, P < 0.05) were higher in women than in men. HSL total activity increased during exercise (47%, P < 0.05) but did not differ between sexes. Accordingly, HSL specific activity (HSL activity per HSL protein content) increased during exercise (62%, P < 0.05) and was generally higher in men than in women (82%, P < 0.05). A similar pattern was observed for HSL Ser(659) phosphorylation, suggesting a role in regulation of HSL activity. Likewise, plasma epinephrine increased during exercise (P < 0.05) and was higher in men than in women during the end of the exercise bout (P < 0.05). We conclude that, although HSL expression and Ser(659) phosphorylation in skeletal muscle during exercise is sex specific, total muscle HSL activity measured in vitro was similar between sexes. The higher basal IMTG content in women compared with men is therefore the best candidate to explain the higher IMTG net hydrolysis during exercise in women.
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Affiliation(s)
- Carsten Roepstorff
- The Copenhagen Muscle Research Centre, Department of Human Physiology, Institute of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark.
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Stettler C, Jenni S, Allemann S, Steiner R, Hoppeler H, Trepp R, Christ ER, Zwahlen M, Diem P. Exercise capacity in subjects with type 1 diabetes mellitus in eu- and hyperglycaemia. Diabetes Metab Res Rev 2006; 22:300-6. [PMID: 16302286 DOI: 10.1002/dmrr.608] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Circumstantial evidence suggests that an increase in plasma glucose availability improves exercise capacity in subjects with type 1 diabetes mellitus. The aim of this study was to assess exercise capacity in eu- and hyperglycaemic conditions in subjects with type 1 diabetes. METHODS Eight moderately exercise-trained male subjects with type 1 diabetes on continuous subcutaneous insulin infusion were studied. Using identical insulin infusion rates, the patients were randomly allocated to perform two stepwise ergometer tests in eu- and hyperglycaemic clamp conditions. The primary endpoint was the peak power output; the secondary endpoints comprised the rate of perceived exertion, lactate levels, heart rate, and respiratory exchange ratio. RESULTS Eu- and hyperglycaemic clamp conditions were observed at a plasma glucose concentration of 5.3 +/- 0.6 mmol/L and 12.4 +/- 2.1 mmol/L, respectively (mean +/- SD), and remained stable throughout the physical exercise. Insulin levels were similar in both conditions. Hyperglycaemia did not result in a significant increase in the peak power output compared to euglycaemia (mean paired difference of 4.96 W, 95% CI - 11.3 to 21.2, p = 0.49). Hyperglycaemia did not have a significant impact on the secondary endpoints compared to euglycaemia. Sensitivity analyses confirmed these results. CONCLUSIONS In subjects with type 1 diabetes, exercise capacity is not influenced by hyperglycaemia. Comparable levels of lactate and similar respiratory exchange ratio suggest that an increase in extracellular glucose availability did not translate into increased intracellular glucose oxidation.
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Affiliation(s)
- Christoph Stettler
- Division of Endocrinology and Diabetes, University of Bern-Inselspital, 3010 Bern, Switzerland.
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Englert V, Wells K, Long W, Hickey MS, Melby CL. Effect of Acute Prior Exercise on Glycemic and Insulinemic Indices. J Am Coll Nutr 2006; 25:195-202. [PMID: 16766777 DOI: 10.1080/07315724.2006.10719532] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Acute exercise is associated with increased insulin sensitivity characterized by increased insulin-induced glucose transport for periods of up to 48 h after the bout of exercise. This suggests that the glycemic response to a meal may be altered by prior exercise. OBJECTIVE We tested the hypothesis that the glycemic and insulinemic responses to a test food consumed following exercise would be lower than when consumed without prior exercise. DESIGN Four lean males (age: 27 +/- 4 y) and 4 females (age: 23 +/- 3 y) completed 3 experimental conditions in random order: ExCHO-Subjects exercised on a cycle ergometer at 70% VO2peak with a net energy cost of 400 kcal, which was followed by consumption of a high carbohydrate (CHO) energy bar; NoExCHO-Same as ExCHO except subjects sat quietly rather than exercised; and NoExGlc-Same as NoExCHO except subjects consumed a 50 g glucose (glc) drink as the reference CHO for GI and insulinemic index (II) determination. For each condition, following exercise or rest, baseline venous blood samples were obtained. Postprandial blood samples were obtained at 15 min intervals for 2 h. RESULTS Neither the 2-h glucose area under the curve (AUC) or the GI were different between ExCHO and NoExCHO. The insulin AUC for ExCHO was 28% lower than the insulin AUC for NoExCHO (p = 0.03). The calculated II for the ExCHO condition was 30% lower than that of NoExCHO (p = 0.05). CONCLUSIONS An acute bout of prior exercise had no effect on the GI of an energy bar compared to that of the same food determined under the standard no-exercise conditions. However, prior exercise resulted in a lower 2-h insulin response to the CHO-rich energy bar.
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Affiliation(s)
- Virginia Englert
- Department of Food Science and Human Nutrition, Nutrition and Metabolic Fitness Laboratory, Colorado State University Fort Collins, CO 80523, USA
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Roepstorff C, Thiele M, Hillig T, Pilegaard H, Richter EA, Wojtaszewski JFP, Kiens B. Higher skeletal muscle alpha2AMPK activation and lower energy charge and fat oxidation in men than in women during submaximal exercise. J Physiol 2006; 574:125-38. [PMID: 16600998 PMCID: PMC1817798 DOI: 10.1113/jphysiol.2006.108720] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
5'AMP-activated protein kinase (AMPK) is an energy sensor activated by perturbed cellular energy status such as during muscle contraction. Activated AMPK is thought to regulate several key metabolic pathways. We used sex comparison to investigate whether AMPK signalling in skeletal muscle regulates fat oxidation during exercise. Moderately trained women and men completed 90 min bicycle exercise at 60% VO2peak. Both AMPK Thr172 phosphorylation and alpha2AMPK activity were increased by exercise in men (approximately 200%, P < 0.001) but not significantly in women. The sex difference in muscle AMPK activation with exercise was accompanied by an increase in muscle free AMP (approximately 164%, P < 0.01), free AMP/ATP ratio (159%, P < 0.05), and creatine (approximately 42%, P < 0.001) in men but not in women (NS), suggesting that lack of AMPK activation in women was due to better maintenance of muscle cellular energy balance compared with men. During exercise, fat oxidation per kg lean body mass was higher in women than in men (P < 0.05). Regression analysis revealed that a higher proportion of type 1 muscle fibres (approximately 23%, P < 0.01) and a higher capillarization (approximately 23%, P < 0.05) in women than in men could partly explain the sex difference in alpha2AMPK activity (r = -0.54, P < 0.05) and fat oxidation (r = 0.64, P < 0.05) during exercise. On the other hand, fat oxidation appeared not to be regulated via AMPK. In conclusion, during prolonged submaximal exercise at 60% VO2peak, higher fat oxidation in women cannot be explained by higher AMPK signalling but is accompanied by improved muscle cellular energy balance in women probably due to sex specific muscle morphology.
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Affiliation(s)
- Carsten Roepstorff
- The Copenhagen Muscle Research Centre, Institute of Exercise and Sport Sciences, Department of Human Physiology, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
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