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Presby DM, Checkley LA, Jackman MR, Higgins JA, Jones KL, Giles ED, Houck JA, Webb PG, Steig AJ, Johnson GC, Rudolph MC, MacLean PS. Regular exercise potentiates energetically expensive hepatic de novo lipogenesis during early weight regain. Am J Physiol Regul Integr Comp Physiol 2019; 317:R684-R695. [PMID: 31553623 DOI: 10.1152/ajpregu.00074.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Exercise is a potent facilitator of long-term weight loss maintenance (WLM), whereby it decreases appetite and increases energy expenditure beyond the cost of the exercise bout. We have previously shown that exercise may amplify energy expenditure through energetically expensive nutrient deposition. Therefore, we investigated the effect of exercise on hepatic de novo lipogenesis (DNL) during WLM and relapse to obesity. Obese rats were calorically restricted with (EX) or without (SED) treadmill exercise (1 h/day, 6 days/wk, 15 m/min) to induce and maintain weight loss. After 6 wk of WLM, subsets of WLM-SED and WLM-EX rats were allowed ad libitum access to food for 1 day to promote relapse (REL). An energy gap-matched group of sedentary, relapsing rats (REL-GM) were provided a diet matched to the positive energy imbalance of the REL-EX rats. During relapse, exercise increased enrichment of hepatic DN-derived lipids and induced hepatic molecular adaptations favoring DNL compared with the gap-matched controls. In the liver, compared with both REL-SED and REL-GM rats, REL-EX rats had lower hepatic expression of genes required for cholesterol biosynthesis; greater hepatic expression of genes that mediate very low-density lipoprotein synthesis and secretion; and greater mRNA expression of Cyp27a1, which encodes an enzyme involved in the biosynthesis of bile acids. Altogether, these data provide compelling evidence that the liver has an active role in exercise-mediated potentiation of energy expenditure during early relapse.
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Affiliation(s)
- David M Presby
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - L Allyson Checkley
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Matthew R Jackman
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Janine A Higgins
- Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Kenneth L Jones
- Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Erin D Giles
- Department of Nutrition and Food Science at Texas A&M University, College Station, Texas
| | - Julie A Houck
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Patricia G Webb
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Amy J Steig
- Center for Human Nutrition at the University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Michael C Rudolph
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Paul S MacLean
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado.,Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado.,Center for Human Nutrition at the University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
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Giles ED, Jackman MR, MacLean PS. Modeling Diet-Induced Obesity with Obesity-Prone Rats: Implications for Studies in Females. Front Nutr 2016; 3:50. [PMID: 27933296 PMCID: PMC5121240 DOI: 10.3389/fnut.2016.00050] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 10/28/2016] [Indexed: 12/03/2022] Open
Abstract
Obesity is a worldwide epidemic, and the comorbidities associated with obesity are numerous. Over the last two decades, we and others have employed an outbred rat model to study the development and persistence of obesity, as well as the metabolic complications that accompany excess weight. In this review, we summarize the strengths and limitations of this model and how it has been applied to further our understanding of human physiology in the context of weight loss and weight regain. We also discuss how the approach has been adapted over time for studies in females and female-specific physiological conditions, such as menopause and breast cancer. As excess weight and the accompanying metabolic complications have become common place in our society, we expect that this model will continue to provide a valuable translational tool to establish physiologically relevant connections to the basic science studies of obesity and body weight regulation.
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Affiliation(s)
- Erin D Giles
- Department of Nutrition and Food Science, Texas A&M University , College Station, TX , USA
| | - Matthew R Jackman
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paul S MacLean
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Leopoldo AS, Lima-Leopoldo AP, Nascimento AF, Luvizotto RAM, Sugizaki MM, Campos DHS, da Silva DCT, Padovani CR, Cicogna AC. Classification of different degrees of adiposity in sedentary rats. Braz J Med Biol Res 2016; 49:e5028. [PMID: 26909787 PMCID: PMC4792506 DOI: 10.1590/1414-431x20155028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 11/17/2015] [Indexed: 01/23/2023] Open
Abstract
In experimental studies, several parameters, such as body weight, body mass index,
adiposity index, and dual-energy X-ray absorptiometry, have commonly been used to
demonstrate increased adiposity and investigate the mechanisms underlying obesity and
sedentary lifestyles. However, these investigations have not classified the degree of
adiposity nor defined adiposity categories for rats, such as normal, overweight, and
obese. The aim of the study was to characterize the degree of adiposity in rats fed a
high-fat diet using cluster analysis and to create adiposity intervals in an
experimental model of obesity. Thirty-day-old male Wistar rats were fed a normal
(n=41) or a high-fat (n=43) diet for 15 weeks. Obesity was defined based on the
adiposity index; and the degree of adiposity was evaluated using cluster analysis.
Cluster analysis allowed the rats to be classified into two groups (overweight and
obese). The obese group displayed significantly higher total body fat and a higher
adiposity index compared with those of the overweight group. No differences in
systolic blood pressure or nonesterified fatty acid, glucose, total cholesterol, or
triglyceride levels were observed between the obese and overweight groups. The
adiposity index of the obese group was positively correlated with final body weight,
total body fat, and leptin levels. Despite the classification of sedentary rats into
overweight and obese groups, it was not possible to identify differences in the
comorbidities between the two groups.
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Affiliation(s)
- A S Leopoldo
- Departamento de Desportos, Centro de Educação Física e Esportes, Universidade Federal do Espírito Santo, Vitória, ES, Brasil
| | - A P Lima-Leopoldo
- Departamento de Desportos, Centro de Educação Física e Esportes, Universidade Federal do Espírito Santo, Vitória, ES, Brasil
| | - A F Nascimento
- Instituto de Ciências da Saúde, Universidade Federal do Mato Grosso, Sinop, MT, Brasil
| | - R A M Luvizotto
- Instituto de Ciências da Saúde, Universidade Federal do Mato Grosso, Sinop, MT, Brasil
| | - M M Sugizaki
- Instituto de Ciências da Saúde, Universidade Federal do Mato Grosso, Sinop, MT, Brasil
| | - D H S Campos
- Departamento de Clínica Médica, Faculdade de Medicina, Universidade Estadual Paulista, Botucatu, SP, Brasil
| | - D C T da Silva
- Departamento de Clínica Médica, Faculdade de Medicina, Universidade Estadual Paulista, Botucatu, SP, Brasil
| | - C R Padovani
- Departamento de Bioestatística, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brasil
| | - A C Cicogna
- Departamento de Clínica Médica, Faculdade de Medicina, Universidade Estadual Paulista, Botucatu, SP, Brasil
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Giles ED, Steig AJ, Jackman MR, Higgins JA, Johnson GC, Lindstrom RC, MacLean PS. Exercise Decreases Lipogenic Gene Expression in Adipose Tissue and Alters Adipocyte Cellularity during Weight Regain After Weight Loss. Front Physiol 2016; 7:32. [PMID: 26903882 PMCID: PMC4748045 DOI: 10.3389/fphys.2016.00032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 01/25/2016] [Indexed: 12/15/2022] Open
Abstract
Exercise is a potent strategy to facilitate long-term weight maintenance. In addition to increasing energy expenditure and reducing appetite, exercise also favors the oxidation of dietary fat, which likely helps prevent weight re-gain. It is unclear whether this exercise-induced metabolic shift is due to changes in energy balance, or whether exercise imparts additional adaptations in the periphery that limit the storage and favor the oxidation of dietary fat. To answer this question, adipose tissue lipid metabolism and related gene expression were studied in obese rats following weight loss and during the first day of relapse to obesity. Mature, obese rats were weight-reduced for 2 weeks with or without daily treadmill exercise (EX). Rats were weight maintained for 6 weeks, followed by relapse on: (a) ad libitum low fat diet (LFD), (b) ad libitum LFD plus EX, or (c) a provision of LFD to match the positive energy imbalance of exercised, relapsing animals. 24 h retention of dietary- and de novo-derived fat were assessed directly using 14C palmitate/oleate and 3H20, respectively. Exercise decreased the size, but increased the number of adipocytes in both retroperitoneal (RP) and subcutaneous (SC) adipose depots, and prevented the relapse-induced increase in adipocyte size. Further, exercise decreased the expression of genes involved in lipid uptake (CD36 and LPL), de novo lipogenesis (FAS, ACC1), and triacylglycerol synthesis (MGAT and DGAT) in RP adipose during relapse following weight loss. This was consistent with the metabolic data, whereby exercise reduced retention of de novo-derived fat even when controlling for the positive energy imbalance. The decreased trafficking of dietary fat to adipose tissue with exercise was explained by reduced energy intake which attenuated energy imbalance during refeeding. Despite having decreased expression of lipogenic genes, the net retention of de novo-derived lipid was higher in both the RP and SC adipose of exercising animals compared to their energy gap-matched controls. Our interpretation of this data is that much of this lipid is being made by the liver and subsequently trafficked to adipose tissue storage. Together, these concerted effects may explain the beneficial effects of exercise on preventing weight regain following weight loss.
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Affiliation(s)
- Erin D Giles
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical CampusAurora, CO, USA
| | - Amy J Steig
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical CampusAurora, CO, USA
| | - Matthew R Jackman
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical CampusAurora, CO, USA
| | - Janine A Higgins
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Department of Pediatrics, University of Colorado Anschutz Medical CampusAurora, CO, USA
| | - Ginger C Johnson
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical CampusAurora, CO, USA
| | - Rachel C Lindstrom
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical CampusAurora, CO, USA
| | - Paul S MacLean
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical CampusAurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical CampusAurora, CO, USA
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Saben JL, Bales ES, Jackman MR, Orlicky D, MacLean PS, McManaman JL. Maternal obesity reduces milk lipid production in lactating mice by inhibiting acetyl-CoA carboxylase and impairing fatty acid synthesis. PLoS One 2014; 9:e98066. [PMID: 24849657 PMCID: PMC4029960 DOI: 10.1371/journal.pone.0098066] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 04/25/2014] [Indexed: 12/21/2022] Open
Abstract
Maternal metabolic and nutrient trafficking adaptations to lactation differ among lean and obese mice fed a high fat (HF) diet. Obesity is thought to impair milk lipid production, in part, by decreasing trafficking of dietary and de novo synthesized lipids to the mammary gland. Here, we report that de novo lipogenesis regulatory mechanisms are disrupted in mammary glands of lactating HF-fed obese (HF-Ob) mice. HF feeding decreased the total levels of acetyl-CoA carboxylase-1 (ACC), and this effect was exacerbated in obese mice. The relative levels of phosphorylated (inactive) ACC, were elevated in the epithelium, and decreased in the adipose stroma, of mammary tissue from HF-Ob mice compared to those of HF-fed lean (HF-Ln) mice. Mammary gland levels of AMP-activated protein kinase (AMPK), which catalyzes formation of inactive ACC, were also selectively elevated in mammary glands of HF-Ob relative to HF-Ln dams or to low fat fed dams. These responses correlated with evidence of increased lipid retention in mammary adipose, and decreased lipid levels in mammary epithelial cells, of HF-Ob dams. Collectively, our data suggests that maternal obesity impairs milk lipid production, in part, by disrupting the balance of de novo lipid synthesis in the epithelial and adipose stromal compartments of mammary tissue through processes that appear to be related to increased mammary gland AMPK activity, ACC inhibition, and decreased fatty acid synthesis.
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Affiliation(s)
- Jessica L. Saben
- Division of Basic Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Graduate Program in Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Elise S. Bales
- Division of Basic Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Matthew R. Jackman
- Center for Human Nutrition, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - David Orlicky
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Paul S. MacLean
- Center for Human Nutrition, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - James L. McManaman
- Division of Basic Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Graduate Program in Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Center for Human Nutrition, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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Wahlig JL, Bales ES, Jackman MR, Johnson GC, McManaman JL, MacLean PS. Impact of high-fat diet and obesity on energy balance and fuel utilization during the metabolic challenge of lactation. Obesity (Silver Spring) 2012; 20:65-75. [PMID: 21720435 PMCID: PMC4109263 DOI: 10.1038/oby.2011.196] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The effects of obesity and a high-fat (HF) diet on whole body and tissue-specific metabolism of lactating dams and their offspring were examined in C57/B6 mice. Female mice were fed low-fat (LF) or HF diets before and throughout pregnancy and lactation. HF-fed mice were segregated into lean (HF-Ln) and obese (HF-Ob) groups before pregnancy by their weight gain response. Compared to LF-Ln dams, HF-Ln, and HF-Ob dams exhibited a greater positive energy balance (EB) and increased dietary fat retention in peripheral tissues (P < 0.05). HF-Ob dams had greater dietary fat retention in liver and adipose compared to HF-Ln dams (P < 0.05). De novo synthesized fat was decreased in tissues and milk from HF-fed dams compared to LF-Ln dams (P < 0.05). However, less dietary and de novo synthesized fat was found in the HF-Ob mammary glands compared to HF-Ln (P < 0.05). Obesity was associated with reduced milk triglycerides relative to lean controls (P < 0.05). Compared to HF diet alone obesity has additional adverse affects, impairing both lipid metabolism as well as milk fat production. Growth rates of LF-Ln litters were lower than HF-Ln and HF-Ob litters (P < 0.05). Total energy expenditure (TEE) of HF-Ob litters was reduced relative to HF-Ln litters, whereas their respiratory exchange ratios (RERs) were increased (P < 0.05). Collectively these data show that consumption of a HF diet significantly affects maternal and neonatal metabolism and that maternal obesity can independently alter these responses.
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Affiliation(s)
- Jessica L. Wahlig
- Department of Obstetrics and Gynecology, Division of Basic Reproductive Sciences, University of Colorado, Denver, Colorado, USA
- Graduate Program in Reproductive Sciences, University of Colorado, Denver, Colorado, USA
| | - Elise S. Bales
- Department of Obstetrics and Gynecology, Division of Basic Reproductive Sciences, University of Colorado, Denver, Colorado, USA
| | - Matthew R. Jackman
- Center for Human Nutrition, University of Colorado, Denver, Colorado, USA
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Colorado, Denver, Colorado, USA
| | - Ginger C. Johnson
- Center for Human Nutrition, University of Colorado, Denver, Colorado, USA
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Colorado, Denver, Colorado, USA
| | - James L. McManaman
- Department of Obstetrics and Gynecology, Division of Basic Reproductive Sciences, University of Colorado, Denver, Colorado, USA
- Graduate Program in Reproductive Sciences, University of Colorado, Denver, Colorado, USA
- Center for Human Nutrition, University of Colorado, Denver, Colorado, USA
- Department of Physiology and Biophysics, University of Colorado, Denver, Colorado, USA
| | - Paul S. MacLean
- Center for Human Nutrition, University of Colorado, Denver, Colorado, USA
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Colorado, Denver, Colorado, USA
- Department of Physiology and Biophysics, University of Colorado, Denver, Colorado, USA
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Even PC, Nadkarni NA, Chaumontet C, Azzout-Marniche D, Fromentin G, Tomé D. Identification of behavioral and metabolic factors predicting adiposity sensitivity to both high fat and high carbohydrate diets in rats. Front Physiol 2011; 2:96. [PMID: 22203804 PMCID: PMC3241340 DOI: 10.3389/fphys.2011.00096] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 11/22/2011] [Indexed: 11/18/2022] Open
Abstract
Individuals exhibit a great variation in their body weight (BW) gain response to a high fat diet. Identification of predictive factors would enable better directed intervention toward susceptible individuals to treat obesity, and uncover potential mechanisms for treatment targeting. We set out to identify predictive behavioral and metabolic factors in an outbred rat model. 12 rats were analyzed in metabolic cages for a period of 5 days during both high carbohydrate diet (HCD), and transition to a high fat diet (HFD). After a recovery period, rats were given a HFD for 6 days to identify those resistant or sensitive to it according to BW gain. Rats were dissected at the end of the study to analyze body composition. This showed that small differences in final BW hid large variations in adiposity, allowing separation of rats into a second classification (final adiposity). Since these rats had been fed a HCD during most of their life, under which most of the adiposity presumably evolved, we considered this carbohydrate-sensitivity or -resistance. Meal size and meal number were found to be good predictors of sensitivity to a HFD, intensity of motor activity and ingestion speed good predictors of sensitivity to a HCD. Rats that were sensitive to the HCD could be resistant to the HFD and vice versa. This points to four types of individuals (carbohydrate/fat resistant/sensitive) though our sample size inhibited deeper investigation of this. This contributes to the idea that to be “obesity prone” does not necessarily need a HFD, it can also happen under a HCD, and be a hidden adiposity change with stable BW.
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Steig AJ, Jackman MR, Giles ED, Higgins JA, Johnson GC, Mahan C, Melanson EL, Wyatt HR, Eckel RH, Hill JO, MacLean PS. Exercise reduces appetite and traffics excess nutrients away from energetically efficient pathways of lipid deposition during the early stages of weight regain. Am J Physiol Regul Integr Comp Physiol 2011; 301:R656-67. [PMID: 21715696 DOI: 10.1152/ajpregu.00212.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The impact of regular exercise on energy balance, fuel utilization, and nutrient availability, during weight regain was studied in obese rats, which had lost 17% of their weight by a calorie-restricted, low-fat diet. Weight reduced rats were maintained for 6 wk with and without regular treadmill exercise (1 h/day, 6 days/wk, 15 m/min). In vivo tracers and indirect calorimetry were then used in combination to examine nutrient metabolism during weight maintenance (in energy balance) and during the first day of relapse when allowed to eat ad libitum (relapse). An additional group of relapsing, sedentary rats were provided just enough calories to create the same positive energy imbalance as the relapsing, exercised rats. Exercise attenuated the energy imbalance by 50%, reducing appetite and increasing energy requirements. Expenditure increased beyond the energetic cost of the exercise bout, as exercised rats expended more energy to store the same nutrient excess in sedentary rats with the matched energy imbalance. Compared with sedentary rats with the same energy imbalance, exercised rats exhibited the trafficking of dietary fat toward oxidation and away from storage in adipose tissue, as well as a higher net retention of fuel via de novo lipogenesis in adipose tissue. These metabolic changes in relapse were preceded by an increase in the skeletal muscle expression of genes involved in lipid uptake, mobilization, and oxidation. Our observations reveal a favorable shift in fuel utilization with regular exercise that increases the energetic cost of storing excess nutrients during relapse and alterations in circulating nutrients that may affect appetite. The attenuation of the biological drive to regain weight, involving both central and peripheral aspects of energy homeostasis, may explain, in part, the utility of regular exercise in preventing weight regain after weight loss.
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Affiliation(s)
- Amy J Steig
- Center for Human Nutrition, University of Colorado Denver, Aurora, CO 80045, USA.
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Abstract
Epidemiological studies have shown a positive relationship between dietary fat intake and obesity. Since rats and mice show a similar relationship, they are considered an appropriate model for studying dietary obesity. The present paper describes the history of using high-fat diets to induce obesity in animals, aims to clarify the consequences of changing the amount and type of dietary fats on weight gain, body composition and adipose tissue cellularity, and explores the contribution of genetics and sex, as well as the biochemical basis and the roles of hormones such as leptin, insulin and ghrelin in animal models of dietary obesity. The major factors that contribute to dietary obesity - hyperphagia, energy density and post-ingestive effects of the dietary fat - are discussed. Other factors that affect dietary obesity including feeding rhythmicity, social factors and stress are highlighted. Finally, we comment on the reversibility of high-fat diet-induced obesity.
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Cabeço LC, Akiba M, Calsa MS, Sartori DRDS, Vicentini-Paulino MDLM, Pinheiro DF. Dieta hiperlipídica com farinha de soja como fonte proteica: utilização na seleção de ratos propensos e resistentes à obesidade. REV NUTR 2010. [DOI: 10.1590/s1415-52732010000300009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJETIVO: Desenvolver uma dieta hiperlipídica de baixo custo, tendo farinha de soja como fonte proteica, que seja eficiente na seleção de ratos propensos e resistentes à obesidade e que permita alcançar fenótipo obeso nos animais propensos. Além desses requisitos, a dieta deve ser palatável e não rejeitada a curto prazo pelo animal. MÉTODOS: A dieta proposta foi obtida misturando-se leite condensado (15,5%), amendoim (18,5%), farinha de soja (20,0%), óleo de milho (6,0%), ração Bio Tec (30,0%) e bolacha wafer de chocolate (10,0%). A mistura foi peletizada e submetida à análise bromatológica. A dieta foi ofertada a ratos Wistar durante uma semana; posteriormente, os animais foram divididos em três grupos, de acordo com o ganho de peso. O terço superior foi considerado propenso à obesidade e o terço inferior, resistente à obesidade. Após 80 dias de oferta da dieta, os animais foram sacrificados e foram quantificados o peso corpóreo, consumo alimentar, gorduras retroperitoneal, periepididimal, de carcaça e gorduras totais. RESULTADOS: Verificou-se que a dieta apresentava 5,31kcal/g, com a seguinte composição: 22,3% de gordura, 22,2% de proteína, 15,9% de fibra, estimando-se 35,7% de carboidrato. Ratos propensos à obesidade, alimentados por 87 dias com a dieta hipercalórica, apresentaram peso corpóreo, gorduras retroperitoneal, periepididimal e totais significativamente maiores do que animais resistentes à obesidade (p<0,05). O consumo de alimentos também foi maior em animais propensos (p<0,05). Verificou-se também que a substituição da caseína pela farinha de soja, como componente proteico da ração, levou à diminuição de 96,0% no custo do estudo. CONCLUSÃO: A dieta formulada com farinha de soja apresentou custo reduzido e foi capaz de desenvolver o fenótipo obeso em ratos propensos, à semelhança do observado na literatura com outras dietas.
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Affiliation(s)
| | - Mayumi Akiba
- Universidade Estadual Paulista Júlio de Mesquita Filho, Brasil
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Bessesen DH, Bull S, Cornier MA. Trafficking of dietary fat and resistance to obesity. Physiol Behav 2008; 94:681-8. [PMID: 18514237 DOI: 10.1016/j.physbeh.2008.04.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 04/02/2008] [Indexed: 11/17/2022]
Abstract
The task of maintaining energy balance involves not only making sure that the number of calories ingested equals the number of calories burned but also involves ensuring nutrient balance. This means that over time, the quantity of carbohydrate, fat and protein consumed equals the amount of each oxidized. While the body has the ability to convert protein to carbohydrate and carbohydrate to fat, over long periods of time the body establishes nutrient balance with a high degree of accuracy storing excess nutrients as fat. To make decisions about food intake, the brain must assimilate information about the quantity of nutrients ingested and their disposition through the body over time. This is a very complex time ordered process as different tissues may be in different states of energy balance at different intervals following food ingestion. The fundamental task for the brain is to assess the influx of nutrients relative to stored pools of those nutrients and the rate at which they are being oxidized. It has been suggested that this task is particularly difficult for dietary fat because the stored pool of lipid is quite large compared to either the stored pools of carbohydrate and protein or the quantity of fat ingested per day. It is clear that some organisms resist weight gain even in the face of highly palatable diets. In fact most individuals eat less on any given day than they could given their maximal capacity for consumption. A central question then is: what restrains food intake in the setting of widely available highly palatable food? In this paper we will discuss the evidence that the movement of dietary fat between tissues may play an important role in the fidelity of nutrient sensing and as a result, resistance or susceptibility to obesity. In particular, the relative metabolism of dietary fat favoring oxidation over storage may be associated with more robust signaling of positive energy balance and resistance to dietary induced obesity in both humans and rats.
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Jackman MR, Steig A, Higgins JA, Johnson GC, Fleming-Elder BK, Bessesen DH, MacLean PS. Weight regain after sustained weight reduction is accompanied by suppressed oxidation of dietary fat and adipocyte hyperplasia. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1117-29. [DOI: 10.1152/ajpregu.00808.2007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A dual-tracer approach (dietary14C-palmitate and intraperitoneal3H-H2O) was used to assess the trafficking of dietary fat and net retention of carbon in triglyceride depots during the first 24 h of weight regain. Obesity-prone male Wistar rats were allowed to mature under obesogenic conditions for 16 wk. One group was switched to ad libitum feeding of a low-fat diet for 10 wk (Obese group). The remaining rats were switched to an energy-restricted, low-fat diet for 10 wk that reduced body weight by 14% and were then assessed in energy balance (Reduced group), with free access to the low-fat diet (Relapse-Day1 group), or with a provision that induced a minor imbalance (+10 kcal) equivalent to that observed in obese rats (Gap-Matched group). Fat oxidation remained at a high, steady rate throughout the day in Obese rats, but was suppressed in Reduced, Gap-Matched, and Relapse-Day1 rats though 9, 18, and 24 h, respectively. The same caloric excess in Obese and Gap-Matched rats led to less fat oxidation over the day and greater trafficking of dietary fat to visceral depots in the latter. In addition to trafficking nutrients to storage, Relapse-Day1 rats had more small, presumably new, adipocytes at the end of 24 h. Dietary fat oxidation at 24 h was related to the phosphorylation of skeletal muscle acetyl-CoA carboxylase and fatty acid availability. These observations provide evidence of adaptations in the oxidation and trafficking of dietary fat that extend beyond the energy imbalance, which facilitate rapid, efficient regain during the relapse to obesity.
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Dourmashkin JT, Chang GQ, Hill JO, Gayles EC, Fried SK, Leibowitz SF. Model for predicting and phenotyping at normal weight the long-term propensity for obesity in Sprague–Dawley rats. Physiol Behav 2006; 87:666-78. [PMID: 16513148 DOI: 10.1016/j.physbeh.2006.01.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2004] [Revised: 12/20/2005] [Accepted: 01/03/2006] [Indexed: 10/25/2022]
Abstract
Tests were conducted to determine whether weight gain or nutrient intake measures during the first week of exposure to a macronutrient diet can accurately predict an animal's long-term propensity towards obesity. In multiple groups of normal-weight Sprague-Dawley rats (n=35-70/group), daily weight gain during the first 5 days on a high-fat diet (45-60% fat) was found to be strongly, positively correlated (r=+0.71 to r=+0.82) with accumulated body fat in 4 dissected depots after 4-6 weeks on the diet. This measure consistently identified obesity-prone (OP) rats which, relative to the obesity-resistant (OR) rats, were only slightly heavier (+15 g, 4%) and hyperphagic (+9 kcal, 8%) after 5 days but markedly heavier (+70g) with up to 2-fold greater fat mass after several weeks on the diet. Other dietary conditions and measures revealed weaker relationships to ultimate body fat accrual. The OP rats identified by their 5-day weight-gain score exhibited at this early stage clear disturbances characteristic of markedly obese rats. These included elevated leptin, insulin, triglycerides and glucose, along with increased lipoprotein lipase activity (LPL) in adipose tissue and galanin expression in the paraventricular nucleus. Most notable were significant reductions in muscle of LPL activity and ratio of beta-hydroxyacyl-CoA dehydrogenase to citrate synthase activity, indicating a decline in lipid transport and capacity of muscle to metabolize lipids. By occurring early with initial weight gain, these hypothalamic and metabolic disturbances in OP rats, favoring fat storage in adipose tissue over fat oxidation in muscle, may have causal relationships to long-term accumulation of body fat.
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Affiliation(s)
- J T Dourmashkin
- The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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Timlin MT, Barrows BR, Parks EJ. Increased dietary substrate delivery alters hepatic fatty acid recycling in healthy men. Diabetes 2005; 54:2694-701. [PMID: 16123359 DOI: 10.2337/diabetes.54.9.2694] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sources of fatty acids flowing to the liver may be used for triacylglycerol (TAG) synthesis. Our objective was to quantify contributions of nonesterified fatty acids (NEFAs), de novo lipogenesis, and dietary fatty acids to VLDL-TAG in the fed state after meal feeding in healthy subjects (n = 6). The effect of substrate delivery rate was also determined by comparison with data obtained under a continuous-feeding regimen. A liquid diet was administered by mouth or via feeding tube. Contributions of NEFAs, de novo lipogenesis, and dietary fatty acids to VLDL-TAG were quantified using stable isotopes and gas chromatography-mass spectrometry. Contribution of NEFAs to VLDL-TAG was similar under meal feeding and continuous feeding, although insulin area under the curve (AUC) was greater under meal feeding (1,597 +/- 455 vs. 471 +/- 484 pmol . h . l(-1), P < 0.004). Lipogenesis achieved a higher AUC with meal feeding versus continuous feeding (88.7 +/- 84.4 vs. 1.9 +/- 19.3 mumol . h . l(-1), P = 0.03) supporting greater stimulation of de novo lipogenesis from increased glucose delivery rate. The contribution of dietary fatty acids to VLDL-TAG was also greater with meal feeding. These data demonstrate for the first time in humans the well-coordinated use of fatty acids by the liver during the transition from fasted to fed states and highlight the dominant role of NEFAs for VLDL-TAG synthesis in both states.
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Affiliation(s)
- Maureen T Timlin
- Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA.
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Wortley KE, Chang GQ, Davydova Z, Leibowitz SF. Peptides that regulate food intake: orexin gene expression is increased during states of hypertriglyceridemia. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1454-65. [PMID: 12560202 DOI: 10.1152/ajpregu.00286.2002] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous reports implicate the orexins in eating and body weight regulation. This study investigated possible functional relationships between hypothalamic orexins and circulating hormones or metabolites. In situ hybridization and quantitative PCR were used to examine orexin expression in the perifornical hypothalamus (PF) of rats and mice on diets varying in fat content and with differential propensity toward obesity. The results showed that orexin gene expression was stimulated by a high-fat diet in close association with elevated triglyceride levels, suggesting a functional relationship between these measures. Results obtained in obesity-prone rats and mice revealed a similar increase in orexin in close relation to triglycerides. A direct test of this orexin-triglyceride link was performed with Intralipid, which increased PF orexin expression along with circulating triglycerides. Whereas PF galanin is similarly stimulated by dietary fat, double-labeling immunofluorescence studies showed that orexin and galanin neurons are anatomically distinct. This evidence suggests that the orexins, like galanin, are "fat-responsive" peptides that respond to circulating lipids.
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Ji H, Friedman MI. Fasting plasma triglyceride levels and fat oxidation predict dietary obesity in rats. Physiol Behav 2003; 78:767-72. [PMID: 12782234 DOI: 10.1016/s0031-9384(03)00078-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated whether fuel metabolism prior to high-fat feeding differs in outbred Sprague-Dawley rats either prone or resistant to diet-induced obesity. Chow-fed rats were deprived of food, and blood was collected 12, 18, and 24 h later. Rats were then fed a high-fat diet ad libitum for up to 4 weeks to assess weight gain. Blood samples were analyzed for a variety of metabolic fuels and hormones. Only fasting plasma triglyceride concentrations showed a positive correlation with the weight gain during the high-fat feeding period, with concentrations after 18 h of fasting showing the most consistent relationship to weight gain. Body weights and fat pad weights did not correlate with fasting plasma triglyceride concentrations before high-fat feeding. The amount of 14CO(2) recovered from gavaged [14C]palmitic acid in chow-fed rats negatively correlated with weight gain during the subsequent period of high-fat feeding. These results show that there are preexisting differences in fat catabolism that may underlie differential susceptibility to diet-induced obesity; in particular, fasting levels of plasma triglycerides and fatty acid oxidation may be early predictive markers for this susceptibility.
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Affiliation(s)
- Hong Ji
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
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Affiliation(s)
- W A Cupples
- Lady Davis Institute, SMBD-Jewish General Hospital, 3755 Cote-Ste-Catherine, Montreal, Quebec, Canada H3T 1E2.
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Affiliation(s)
- W A Cupples
- Lady Davis Institute, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2
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