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Zhu S, Feng X, Feng X, Xie K, Li Y, Chen L, Mo Y, Liang J, Wu X, Sun Z, Shu G, Wang S, Gao P, Zhu X, Zhu C, Jiang Q, Wang L. Diet containing stearic acid increased food intake in mice by reducing serum leptin compared with oleic acid. Food Funct 2023; 14:990-1002. [PMID: 36545693 DOI: 10.1039/d2fo03051a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In today's society, obesity is becoming increasingly serious, and controlling food intake and maintaining weight balance have become increasingly important. Here, we found that a stearic acid diet can increase food intake without causing obesity in mice compared with an oleic acid diet. Stearic acid increases food intake in mice by reducing serum leptin and increasing NPY neuronal excitability through the JAK2/STAT3 pathway. The impaired anorexic effect of leptin is probably due to repressive cholesterol-oxysterol-LXR-α/SREBP-1c-mediated leptin expression in mouse iWAT. At the same time, we found that stearic acid was not only poorly absorbed by itself in the small intestine but also reduced the entire absorption system of the small intestine. In conclusion, we have proven that a stearic acid diet can increase food intake in mice and avoid obesity, but whether a stearic acid diet could cause adverse reactions in the body remains to be studied.
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Affiliation(s)
- Shuqing Zhu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xiaohua Feng
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xiajie Feng
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Kailai Xie
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yongxiang Li
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Ave., Room 8070, Houston, TX 77030, USA.
| | - Lvshuang Chen
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yingfen Mo
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jingwen Liang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xin Wu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhonghua Sun
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Gang Shu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Songbo Wang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Ping Gao
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xiaotong Zhu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Canjun Zhu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Qingyan Jiang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Lina Wang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong 510642, China.,National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
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Reichelt K, Niebisch AM, Kacza J, Schoeniger A, Fuhrmann H. The Bovine Hepatic Cell Line BFH12 as a Possible Model for Hepatosteatosis in Dairy Cows. Front Vet Sci 2022; 9:840202. [PMID: 35359674 PMCID: PMC8963807 DOI: 10.3389/fvets.2022.840202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
Hepatosteatosis is a common metabolic disorder of dairy cows, especially during early lactation. Currently, there are a few models of bovine hepatic steatosis available, including primary hepatocytes, liver slices, and animal models. Studies that elucidate the influence of single fatty acids on lipid classes, fatty acid pattern, gene expression, and phenotypic changes are still limited. Hence, we investigated the suitability of the fetal bovine hepatocyte-derived cell line BFH12 as a model for hepatosteatosis. To create a steatotic environment, we treated BFH12 with stearic acid, palmitic acid, or oleic acid in non-toxic doses. Thin-layer chromatography and gas chromatography were used to analyze lipid classes and fatty acid pattern, and qPCR was used to quantify gene expression of relevant target genes. Lipid droplets were visualized with confocal laser scanning microscopy and evaluated for number and size. Treatment with oleic acid increased triglycerides, as well as lipid droplet count per cell and upregulated carnitine palmitoyl transferase 1, which correlates with findings of in vivo models. Oleic acid was largely incorporated into triglycerides, phospholipids, and non-esterified fatty acids. Stearic acid was found mainly in non-esterified fatty acids and triglycerides, whereas palmitic acid was mainly desaturated to palmitoleic acid. All three fatty acids downregulated stearyl-CoA-desaturase 1. In conclusion, BFH12 can acquire a steatotic phenotype by incorporating and accumulating fatty acids. Oleic acid is particularly suitable to produce hepatosteatosis. Therefore, BFH12 may be a useful in vitro model to study bovine hepatosteatosis and its underlying molecular mechanisms.
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Affiliation(s)
- Kristin Reichelt
- Faculty of Veterinary Medicine, Institute of Biochemistry, University of Leipzig, Leipzig, Germany
- *Correspondence: Kristin Reichelt
| | - Anna M. Niebisch
- Faculty of Veterinary Medicine, Institute of Biochemistry, University of Leipzig, Leipzig, Germany
| | - Johannes Kacza
- BioImaging Core Facility, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Axel Schoeniger
- Faculty of Veterinary Medicine, Institute of Biochemistry, University of Leipzig, Leipzig, Germany
| | - Herbert Fuhrmann
- Faculty of Veterinary Medicine, Institute of Biochemistry, University of Leipzig, Leipzig, Germany
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Ratnappan R, Ward JD, Yamamoto KR, Ghazi A. Nuclear hormone receptors as mediators of metabolic adaptability following reproductive perturbations. WORM 2016; 5:e1151609. [PMID: 27073739 DOI: 10.1080/21624054.2016.1151609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 01/21/2016] [Accepted: 02/01/2016] [Indexed: 01/13/2023]
Abstract
Previously, we identified a group of nuclear hormone receptors (NHRs) that promote longevity in the nematode Caenorhabditis elegans following germline-stem cell (GSC) loss. This group included NHR-49, the worm protein that performs functions similar to vertebrate PPARα, a key regulator of lipid metabolism. We showed that NHR-49/PPARα enhances mitochondrial β-oxidation and fatty acid desaturation upon germline removal, and through the coordinated enhancement of these processes allows the animal to retain lipid homeostasis and undergo lifespan extension. NHR-49/PPARα expression is elevated in GSC-ablated animals, in part, by DAF-16/FOXO3A and TCER-1/TCERG1, two other conserved, pro-longevity transcriptional regulators that are essential for germline-less longevity. In exploring the roles of the other pro-longevity NHRs, we discovered that one of them, NHR-71/HNF4, physically interacted with NHR-49/PPARα. NHR-71/HNF4 did not have a broad impact on the expression of β-oxidation and desaturation targets of NHR-49/PPARα. But, both NHR-49/PPARα and NHR-71/HNF4 were essential for the increased expression of DAF-16/FOXO3A- and TCER-1/TCERG1-downstream target genes. In addition, nhr-49 inactivation caused a striking membrane localization of KRI-1, the only known common upstream regulator of DAF-16/FOXO3A and TCER-1/TCERG1, suggesting that it may operate in a positive feedback loop to potentiate the activity of this pathway. These data underscore how selective interactions between NHRs that function as nodes in metabolic networks, confer functional specificity in response to different physiological stimuli.
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Affiliation(s)
- Ramesh Ratnappan
- Department of Pediatrics, University of Pittsburgh School of Medicine , Pittsburgh, PA, USA
| | - Jordan D Ward
- Department of Cellular and Molecular Pharmacology, University of California , San Francisco, San Francisco, CA, USA
| | - Keith R Yamamoto
- Department of Cellular and Molecular Pharmacology, University of California , San Francisco, San Francisco, CA, USA
| | - Arjumand Ghazi
- Department of Pediatrics, University of Pittsburgh School of Medicine , Pittsburgh, PA, USA
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Janssens S, Heemskerk MM, van den Berg SA, van Riel NA, Nicolay K, Willems van Dijk K, Prompers JJ. Effects of low-stearate palm oil and high-stearate lard high-fat diets on rat liver lipid metabolism and glucose tolerance. Nutr Metab (Lond) 2015; 12:57. [PMID: 26691906 PMCID: PMC4683731 DOI: 10.1186/s12986-015-0053-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/11/2015] [Indexed: 01/01/2023] Open
Abstract
Background Excess consumption of energy-dense, high-fat Western diets contributes to the development of obesity and obesity-related disorders, such as fatty liver disease. However, not only the quantity but also the composition of dietary fat may play a role in the development of liver steatosis. The aim of this study was to determine the effects of low-stearate palm oil and high-stearate lard high-fat diets on in vivo liver lipid metabolism. Methods Wistar rats were fed with either normal chow (CON), a high-fat diet based on palm oil (HFP), or a high-fat diet based on lard (HFL). After 10 weeks of diet, magnetic resonance spectroscopy was applied for the in vivo determination of intrahepatocellular lipid content and the uptake and turnover of dietary fat after oral administration of 13C-labeled lipids. Derangements in liver lipid metabolism were further assessed by measuring hepatic very-low density lipoprotein (VLDL) secretion and ex vivo respiratory capacity of liver mitochondria using fat-derived substrates. In addition, whole-body and hepatic glucose tolerance were determined with an intraperitoneal glucose tolerance test. Results Both high-fat diets induced liver lipid accumulation (p < 0.001), which was accompanied by a delayed uptake and/or slower turnover of dietary fat in the liver (p < 0.01), but without any change in VLDL secretion rates. Surprisingly, liver lipid content was higher in HFP than in HFL (p < 0.05), despite the increased fatty acid oxidative capacity in isolated liver mitochondria of HFP animals (p < 0.05). In contrast, while both high-fat diets induced whole-body glucose intolerance, only HFL impaired hepatic glucose tolerance. Conclusion High-fat diets based on palm oil and lard similarly impair the handling of dietary lipids in the liver, but only the high-fat lard diet induces hepatic glucose intolerance.
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Affiliation(s)
- Sharon Janssens
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Mattijs M Heemskerk
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Sjoerd A van den Berg
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands ; Present address: Amphia Hospital, Breda, The Netherlands
| | - Natal A van Riel
- Computational Biology, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ko Willems van Dijk
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands ; Department of Medicine, division Endocrinology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
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Shen MC, Zhao X, Siegal GP, Desmond R, Hardy RW. Dietary stearic acid leads to a reduction of visceral adipose tissue in athymic nude mice. PLoS One 2014; 9:e104083. [PMID: 25222131 PMCID: PMC4164353 DOI: 10.1371/journal.pone.0104083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 07/10/2014] [Indexed: 01/27/2023] Open
Abstract
Stearic acid (C18:0) is a long chain dietary saturated fatty acid that has been shown to reduce metastatic tumor burden. Based on preliminary observations and the growing evidence that visceral fat is related to metastasis and decreased survival, we hypothesized that dietary stearic acid may reduce visceral fat. Athymic nude mice, which are used in models of human breast cancer metastasis, were fed a stearic acid, linoleic acid (safflower oil), or oleic acid (corn oil) enriched diet or a low fat diet ad libitum. Total body weight did not differ significantly between dietary groups over the course of the experiment. However visceral fat was reduced by ∼70% in the stearic acid fed group compared to other diets. In contrast total body fat was only slightly reduced in the stearic acid diet fed mice when measured by dual-energy x-ray absorptiometry and quantitative magnetic resonance. Lean body mass was increased in the stearic acid fed group compared to all other groups by dual-energy x-ray absorptiometry. Dietary stearic acid significantly reduced serum glucose compared to all other diets and increased monocyte chemotactic protein-1 (MCP-1) compared to the low fat control. The low fat control diet had increased serum leptin compared to all other diets. To investigate possible mechanisms whereby stearic acid reduced visceral fat we used 3T3L1 fibroblasts/preadipocytes. Stearic acid had no direct effects on the process of differentiation or on the viability of mature adipocytes. However, unlike oleic acid and linoleic acid, stearic acid caused increased apoptosis (programmed cell death) and cytotoxicity in preadipocytes. The apoptosis was, at least in part, due to increased caspase-3 activity and was associated with decreased cellular inhibitor of apoptosis protein-2 (cIAP2) and increased Bax gene expression. In conclusion, dietary stearic acid leads to dramatically reduced visceral fat likely by causing the apoptosis of preadipocytes.
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Affiliation(s)
- Ming-Che Shen
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Xiangmin Zhao
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Gene P. Siegal
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Departments of Cell, Developmental & Integrative Biology and Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Medicine, Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Renee Desmond
- Department of Medicine, Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Robert W. Hardy
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Medicine, Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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van den Berg SA, Guigas B, Bijland S, Ouwens M, Voshol PJ, Frants RR, Havekes LM, Romijn JA, van Dijk KW. High levels of dietary stearate promote adiposity and deteriorate hepatic insulin sensitivity. Nutr Metab (Lond) 2010; 7:24. [PMID: 20346174 PMCID: PMC2852377 DOI: 10.1186/1743-7075-7-24] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 03/27/2010] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Relatively little is known about the role of specific saturated fatty acids in the development of high fat diet induced obesity and insulin resistance. Here, we have studied the effect of stearate in high fat diets (45% energy as fat) on whole body energy metabolism and tissue specific insulin sensitivity. METHODS C57Bl/6 mice were fed a low stearate diet based on palm oil or one of two stearate rich diets, one diet based on lard and one diet based on palm oil supplemented with tristearin (to the stearate level of the lard based diet), for a period of 5 weeks. Ad libitum fed Oxidative metabolism was assessed by indirect calorimetry at week 5. Changes in body mass and composition was assessed by DEXA scan analysis. Tissue specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analysis and Western blot at the end of week 5. RESULTS Indirect calorimetry analysis revealed that high levels of dietary stearate resulted in lower caloric energy expenditure characterized by lower oxidation of fatty acids. In agreement with this metabolic phenotype, mice on the stearate rich diets gained more adipose tissue mass. Whole body and tissue specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp and analysis of insulin induced PKBser473 phosphorylation. Whole body insulin sensitivity was decreased by all high fat diets. However, while insulin-stimulated glucose uptake by peripheral tissues was impaired by all high fat diets, hepatic insulin sensitivity was affected only by the stearate rich diets. This tissue-specific pattern of reduced insulin sensitivity was confirmed by similar impairment in insulin-induced phosphorylation of PKBser473 in both liver and skeletal muscle. CONCLUSION In C57Bl/6 mice, 5 weeks of a high fat diet rich in stearate induces a metabolic state favoring low oxidative metabolism, increased adiposity and whole body insulin resistance characterized by severe hepatic insulin resistance. These results indicate that dietary fatty acid composition per sé rather than dietary fat content determines insulin sensitivity in liver of high fat fed C57Bl/6 mice.
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Affiliation(s)
- Sjoerd Aa van den Berg
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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Brock TJ, Browse J, Watts JL. Fatty acid desaturation and the regulation of adiposity in Caenorhabditis elegans. Genetics 2007; 176:865-75. [PMID: 17435249 PMCID: PMC1894614 DOI: 10.1534/genetics.107.071860] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Monounsaturated fatty acids are essential components of membrane and storage lipids. Their synthesis depends on the conversion of saturated fatty acids to unsaturated fatty acids by Delta9 desaturases. Caenorhabditis elegans has three Delta9 desaturases encoded by the genes fat-5, fat-6, and fat-7. We generated nematodes that display a range of altered fatty acid compositions by constructing double-mutant strains that combine mutations in fat-5, fat-6, and fat-7. All three double-mutant combinations have reduced survival at low temperatures. The fat-5;fat-6 double mutants display relatively subtle fatty acid composition alterations under standard conditions, but extreme fatty acid composition changes and reduced survival in the absence of food. The strain with the most severe defect in the production of unsaturated fatty acids, fat-6;fat-7, exhibits slow growth and reduced fertility. Strikingly, the fat-6;fat-7 double-mutant animals have decreased fat stores and increased expression of genes involved in fatty acid oxidation. We conclude that the Delta9 desaturases, in addition to synthesizing unsaturated fatty acids for properly functioning membranes, play key roles in lipid partitioning and in the regulation of fat storage.
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Affiliation(s)
| | | | - Jennifer L. Watts
- Corresponding author: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340. E-mail:
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Abstract
Coming from the Greek for "hard fat," stearic acid represents one of the most abundant FA in the Western diet. Otherwise known as n-octadecanoic acid (18:0), stearate is either obtained in the diet or synthesized by the elongation of palmitate, the principal product of the FA synthase system in animal cells. Stearic acid has been shown to be a very poor substrate for TG synthesis, even as compared with other saturated fats such as myristate and palmitate, and in human studies stearic acid has been shown to generate a lower lipemic response than medium-chain saturated FA. Although it has been proposed that this may be due to less efficient absorption of stearic acid in the gut, such findings have not been consistent. Along with palmitate, stearate is the major substrate for the enzyme stearoyl-CoA desaturase, which catalyzes the conversion of stearate to oleate, the preferred substrate for the synthesis of TG and other complex lipids. In mice, targeted disruption of the stearoyl-CoA desaturase-1 (SCD1) gene results in the generation of a lean mouse that is resistant to diet-induced obesity and insulin resistance. SCD1 also has been shown to be a key target of the anorexigenic hormone leptin, thus underscoring the importance of this enzyme, and consequently the cellular stearate-to-oleate ratio, in lipid metabolism and potentially in the treatment of obesity and related disorders.
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Affiliation(s)
- Harini Sampath
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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9
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Treadwell RM, Pronczuk A, Hayes KC. Glyceride stearic acid content and structure affect the energy available to growing rats. J Nutr 2002; 132:3356-62. [PMID: 12421851 DOI: 10.1093/jn/132.11.3356] [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: 11/13/2022] Open
Abstract
To better understand the relative absorption of 18:0, specific structured triglycerides (STG) with varied ratios of 18:0 and short-chain organic acids (2:0, 3:0, 4:0) were compared with naturally occurring 18:0 in cocoa butter and to other mono- and diglycerides (DGs) containing 18:0. A bioassay for available fat energy was developed for growing Sprague-Dawley rats fed reduced energy from a control diet containing an American Heart Association (AHA) fat blend to generate 60 or 80% normal growth. The resulting standard growth curve was applied to the test fats, including cocoa butter and six glycerides, which were blended 3:1 with the AHA blend (to ensure EFA sufficiency) and pair-fed to match intake of control rats (AHA diet, 80% normal growth). Available energy from test fats ranged from 30 to 12 kJ/g (7.1 to 2.9 kcal/g) for cocoa butter to 18:0-DG, respectively, with the mean of the four different STG being 22 kJ/g (5.2 kcal/g). Energy available from test fats was negatively related to total 18:0 in the STG (r = -0.90; P < 0.001) and fecal dry weight (r = -0.92; P < 0.001); the effect was greater for monoglyceride (monolong-18:0) than for DG (dilong-18:0) but was not related to fecal 18:0. Compared with monoglyceride-18:0, available energy was increased or decreased when short-chain organic acids (SCOA) were added to form triglycerides, depending on the addition of butyrate or acetate, respectively. The different fat sources altered the available energy without apparent changes in lipoproteins or body composition. Thus, the reduced energy available from a glyceride containing 18:0 is determined by its total 18:0 and reflects the mono- or dilong chain character of the glyceride, its content of SCOA and triglyceride structure or organization per se.
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Affiliation(s)
- Robyn M Treadwell
- Foster Biomedical Research Laboratory, Brandeis University, Waltham, MA 02254, USA
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Tachibana S, Sato K, Takahashi T, Akiba Y. Octanoate inhibits very low-density lipoprotein secretion in primary cultures of chicken hepatocytes. Comp Biochem Physiol A Mol Integr Physiol 2002; 132:621-7. [PMID: 12044771 DOI: 10.1016/s1095-6433(02)00103-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of octanoate, a medium-chain fatty acid, on very low-density lipoprotein (VLDL) secretion in primary cultures of chicken hepatocytes were compared with those of palmitate. Palmitate added to the incubation media at concentrations up to 0.36 mM increased intracellular triacylglycerol (TG) accumulation and VLDL-TG secretion in a concentration-dependent manner, whereas the addition of octanoate alone (0.21-0.6 mM) did not change these parameters. VLDL-TG secretion from hepatocytes cultured in media to which 0.6 or 1.0 mM octanoate had been added in the presence of 0.21 mM palmitate was significantly lower than that obtained under control incubation conditions (0.21 mM palmitate only). The addition of 1.0 mM octanoate to the incubation media with or without 0.21 mM palmitate decreased VLDL apolipoprotein B (apoB) secretion. These results demonstrate that the addition of octanoate to primary cultures of chicken hepatocytes reduces VLDL secretion in respect of both TG and apoB secretion. It is suggested that medium-chain fatty acids are a factor modulating VLDL secretion, which plays a key role in fat deposition in chickens.
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Affiliation(s)
- Shizuko Tachibana
- Graduate School of Agricultural Science, Tohoku University, Aoba-Ku, Sendai 981-8555, Japan
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Commerford SR, Pagliassotti MJ, Melby CL, Wei Y, Hill JO. Inherent capacity for lipogenesis or dietary fat retention is not increased in obesity-prone rats. Am J Physiol Regul Integr Comp Physiol 2001; 280:R1680-7. [PMID: 11353671 DOI: 10.1152/ajpregu.2001.280.6.r1680] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Obesity results from positive energy balance and, perhaps, abnormalities in lipid and glycogen metabolism. The purpose of this study was to determine whether differences in lipogenesis, retention of dietary fat, and/or glycogenesis influenced susceptibility to dietary obesity. After 1 wk of free access to a high-fat diet (HFD; 45% fat by energy) rats were separated on the basis of 1 wk body weight gain into obesity-prone (OP; > or =48 g) or obesity-resistant groups (OR; < or =40 g). Rats were either studied at this time (OR1, OP1) or continued on the HFD for an additional 4 wk (OR5, OP5). Weight gain and energy intake were greater (P < or = 0.05) in OP vs. OR at both 1 (53 +/- 2 vs. 34 +/- 1 g; 892 +/- 27 vs. 755 +/- 14 kcal) and 5 (208 +/- 7 vs. 170 +/- 7 g; 4,484 +/- 82 vs. 4,008 +/- 72 kcal) wk, respectively. Rats were injected with (3)H(2)O and were either provided free access to an HFD meal containing labeled fatty acids (fed; n = 10 or 11/group) or were fasted (n = 10/group) overnight. The amount of food or (14)C tracer eaten overnight was equivalent between OP and OR rats. In liver, the fraction of (3)H retained in glycogen or lipid was not significantly different between OR and OP groups. Retention of dietary fat in the liver was not increased in OP rats. In adipose tissue, retention of (3)H was approximately 49% greater (P < or = 0.05) in OP1 vs. OR1 and approximately 30% greater in OP5 vs. OR5, but retention of dietary fat was not elevated in OP vs. OR. At the same time, fat pad weight (sum of epididymal, retroperitoneal, mesenteric) was 49% greater in OP1 rats vs. OR1 rats and 65% greater in OP5 vs. OR5 rats (P < or = 0.05). Thus a greater capacity for lipogenesis or retention of dietary fat does not appear to be included in the OP phenotype. The characteristic increase in energy intake associated with OP rats appears to be necessary and critical to accelerated weight and fat gain.
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Affiliation(s)
- S R Commerford
- Department of Pediatrics, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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Rioux V, Lemarchal P, Legrand P. Myristic acid, unlike palmitic acid, is rapidly metabolized in cultured rat hepatocytes. J Nutr Biochem 2000; 11:198-207. [PMID: 10827342 DOI: 10.1016/s0955-2863(00)00065-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study was designed to examine and compare the metabolism of myristic and palmitic acids in cultured rat hepatocytes. [1-(14)C]-Labeled fatty acids were solubilized with albumin at 0.1 mmol/L in culture medium. Incubation with 24-hr cultured hepatocytes was carried out for 12 hr. Myristic acid was more rapidly (P < 0.05) taken up by the cells than was palmitic acid (86.9 +/- 0.9% and 68.3 +/- 5.7%, respectively, of the initial radioactivity was cleared from the medium after 4 hr incubation). Incorporation into cellular lipids, however, was similar after the same time (33.4 +/- 2.8% and 34.9 +/- 9.3%, respectively, of initial radioactivity). In the early phase of the incubation (30 min), myristic acid was more rapidly incorporated into cellular triglycerides than was palmitic acid (7.4 +/- 0.9% and 3.6 +/- 1.9%, respectively, of initial radioactivity). However, after 12 hr incubation, the radioactivity of cellular triglycerides, cellular phospholipids, and secreted triglycerides was significantly higher with palmitic acid as precursor. Myristic acid oxidation was significantly higher than that of palmitic acid (14.9 +/- 2.2% and 2.3 +/- 0.6%, respectively, of the initial radioactivity was incorporated into the beta-oxidation products after 4 hr). Myristic acid was also more strongly elongated to radiolabeled palmitic acid (12.2 +/- 0.8% of initial radioactivity after 12 hr) than palmitic acid was to stearic acid (5.1 +/- 1.3% of initial radioactivity after 12 hr). The combination of elongation and beta-oxidation results in the rapid disappearance of C14:0 in hepatocytes whereas C16:0 is esterified to form glycerolipids. This study provides evidence that myristic acid is more rapidly metabolized in cultured hepatocytes than is palmitic acid.
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Affiliation(s)
- V Rioux
- Laboratoire de Biochimie, INRA-ENSA, Rennes, France
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Pai T, Yeh YY. Desaturation of stearate is insufficient to increase the concentrations of oleate in cultured rat hepatocytes. J Nutr 1997; 127:753-7. [PMID: 9164997 DOI: 10.1093/jn/127.5.753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Desaturation of stearate and palmitate and its effect on cellular accumulation of oleate were determined in primary culture of rat hepatocytes. The rate of oleate synthesis as measured by the formation of monounsaturated fatty acids from stearate was significantly higher than that from palmitate. The rate of [1-(14)C]stearate incorporation into oleate [1208 +/- 195 pmol/(mg protein x 4 h)] was 80% higher than that of [1-(14)C]palmitate [(672 +/- 82 pmol/(mg protein x 4 h)]. Despite the different rates of desaturation, the cellular oleate concentrations did not differ in the cells treated with stearate and palmitate (i.e., 42.5 +/- 4.5 vs. 40.8 +/- 5.2 nmol/mg protein). On the other hand, oleate concentration in the cells incubated with exogenous oleate was 198.1 +/- 9.5 nmol/mg protein. There was a dose-dependent increase in cellular stearate concentration by increasing stearate concentrations from 0.5 mmol/L to 4.0 mmol/L in culture medium. A linear increase in cellular stearate concentration was also achieved by increasing the duration of incubation with 1.0 mmol/L stearate from 2 to 24 h. Despite the marked increases in stearate concentrations under these conditions, oleate concentrations remained unchanged in the cells. These results do not support the contention that the hypocholesterolemic effect of stearate may be mediated by its conversion to oleate, although stearate is a more favorable substrate for desaturation than palmitate.
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Affiliation(s)
- T Pai
- Nutrition Department, The Pennsylvania State University, University Park 16802, USA
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Pai T, Yeh YY. Stearic acid modifies very low density lipoprotein lipid composition and particle size differently from shorter-chain saturated fatty acids in cultured rat hepatocytes. Lipids 1997; 32:143-9. [PMID: 9075203 DOI: 10.1007/s11745-997-0018-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Stearic acid as compared to myristate, palmitate, or oleate is poorly incorporated into triacylglycerol, a major lipid component of very low density lipoprotein (VLDL). The present study investigated the effects of these fatty acids on VLDL metabolism in cultured rat hepatocytes. All fatty acids stimulated [2-3H] glycerol incorporation into VLDL lipids and secretion of [3H]-labeled VLDL by hepatocytes. However, the rate of [3H]-labeled VLDL secretion in the presence of nonlabeled stearate (12.8 +/- 0.7 pmol/mg protein/4 h) was 46, 59, and 22% of that observed for those treated with myristate, palmitate, and oleate, respectively. [1-14C]Stearate as a substrate was also less effective than other labeled fatty acids to be incorporated into VLDL lipids. Of total VLDL lipids synthesized from [1-14C] stearate, triacylglycerol accounted for 78% as compared to 88-97% of that derived from palmitate, myristate, and oleate. The amounts of apoB100 and apoB48 were the same in hepatocytes treated with or without exogenous fatty acids. Similarly, the rate of apoB synthesis from [35S] methionine was not affected by exogenous fatty acids. The treatment of cells with various saturated fatty acids increased the particle size of VLDL to different extents. The largest particles of VLDL, with a mean diameter of 79.3 +/- 11.9 nm, were seen in the cells treated with stearate, followed by those treated with palmitate and myristate (45.5 +/- 9.8 and 38.6 +/- 6.8 nm, diameter, respectively). Clearly, hepatocytes treated with stearate secrete less VLDL and produce larger VLDL particles than those treated with shorter-chain saturated fatty acids.
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Affiliation(s)
- T Pai
- Department of Nutrition, Pennsylvania State University, University Park 16802, USA
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