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Chandrasekaran P, Murugan S, Richard E, Bethapudi B, Purusothaman D, Velusami C, D'Souza P, Mundkinajeddu D, Talkad M. Evaluation of lipotropic effect of herbal formulation on hepatic fat accumulation in rats fed with methionine-choline deficient diet. Pharmacogn Mag 2019. [DOI: 10.4103/pm.pm_111_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Lee KH, Song JL, Park ES, Ju J, Kim HY, Park KY. Anti-Obesity Effects of Starter Fermented Kimchi on 3T3-L1 Adipocytes. Prev Nutr Food Sci 2015; 20:298-302. [PMID: 26770918 DOI: 10.3746/pnf.2015.20.4.298] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 11/23/2015] [Indexed: 01/01/2023] Open
Abstract
The anti-obesity effects of starter (Leuconostoc mesenteroides+Lactobacillus plantarum) fermented kimchi on 3T3-L1 adipocyte were studied using naturally fermented kimchi (NK), a functional kimchi (FK, NK supplemented with green tea), and FK supplemented with added starters (FKS). Oil red O staining and cellular levels of triglyceride (TG) and glycerol were used to evaluate the in vitro anti-obesity effects of these kimchis in 3T3-L1 cells. The expressions of adipogenesis/lipogenesis-related genes of peroxisome proliferator-active receptor (PPAR)-γ, CCAAT/enhance-binding protein (C/EBP)-α, and fatty acid synthase (FAS) were determined by RT-PCR. Kimchis, especially FKS, markedly decreased TG levels and increased levels of intracellular glycerol and lipid lipolysis. In addition, FKS also reduced the mRNA levels of PPAR-γ, C/EBP-α, and FAS, which are related to adipogenesis/lipogenesis in 3T3-L1 cells. These results suggest the anti-obesity effects of FKS were to due to enhanced lipolysis and reduced adipogenesis/lipogenesis in 3T3-L1 adipocytes.
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Affiliation(s)
- Kyung-Hee Lee
- Department of Food Science and Nutrition, and Kimchi Research Institute, Pusan National University, Busan 46241, Korea
| | - Jia-Le Song
- Department of Food Science and Nutrition, and Kimchi Research Institute, Pusan National University, Busan 46241, Korea; Department of Nutrition and Food Hygiene, School of Public Health, Guilin Medical University, Guilin, Guangxi 541004, People's Republic of China
| | - Eui-Seong Park
- Department of Food Science and Nutrition, and Kimchi Research Institute, Pusan National University, Busan 46241, Korea
| | - Jaehyun Ju
- Department of Food Science and Nutrition, and Kimchi Research Institute, Pusan National University, Busan 46241, Korea
| | - Hee-Young Kim
- Department of Food Science and Nutrition, and Kimchi Research Institute, Pusan National University, Busan 46241, Korea
| | - Kun-Young Park
- Department of Food Science and Nutrition, and Kimchi Research Institute, Pusan National University, Busan 46241, Korea
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Park HS, Shim SM, Kim GH. Silydianin in chloroform soluble fraction of Cirsium japonicum leaf inhibited adipocyte differentiation by regulating adipogenic transcription factors and enzymes. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13765-013-3216-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Iori E, Vinci B, Murphy E, Marescotti MC, Avogaro A, Ahluwalia A. Glucose and fatty acid metabolism in a 3 tissue in-vitro model challenged with normo- and hyperglycaemia. PLoS One 2012; 7:e34704. [PMID: 22509346 PMCID: PMC3324505 DOI: 10.1371/journal.pone.0034704] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/08/2012] [Indexed: 11/18/2022] Open
Abstract
Nutrient balance in the human body is maintained through systemic signaling between different cells and tissues. Breaking down this circuitry to its most basic elements and reconstructing the metabolic network in-vitro provides a systematic method to gain a better understanding of how cross-talk between the organs contributes to the whole body metabolic profile and of the specific role of each different cell type. To this end, a 3-way connected culture of hepatocytes, adipose tissue and endothelial cells representing a simplified model of energetic substrate metabolism in the visceral region was developed. The 3-way culture was shown to maintain glucose and fatty acid homeostasis in-vitro. Subsequently it was challenged with insulin and high glucose concentrations to simulate hyperglycaemia. The aim was to study the capacity of the 3-way culture to maintain or restore normal circulating glucose concentrations in response to insulin and to investigate the effects these conditions on other metabolites involved in glucose and lipid metabolism. The results show that the system’s metabolic profile changes dramatically in the presence of high concentrations of glucose, and that these changes are modulated by the presence of insulin. Furthermore, we observed an increase in E-selectin levels in hyperglycaemic conditions and increased IL-6 concentrations in insulin-free-hyperglycaemic conditions, indicating, respectively, endothelial injury and proinflammatory stress in the challenged 3-way system.
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Affiliation(s)
- Elisabetta Iori
- Division of Metabolic Diseases, Department of Clinical and Experimental Medicine, University of Padua, Padua, Italy
| | - Bruna Vinci
- Centro Interdipartimentale di Ricerca ″E.Piaggio″, University of Pisa, Pisa, Italy
- CNR Institute of Clinical Physiology, Pisa, Italy
| | - Ellen Murphy
- Division of Metabolic Diseases, Department of Clinical and Experimental Medicine, University of Padua, Padua, Italy
| | - Maria Cristina Marescotti
- Division of Metabolic Diseases, Department of Clinical and Experimental Medicine, University of Padua, Padua, Italy
| | - Angelo Avogaro
- Division of Metabolic Diseases, Department of Clinical and Experimental Medicine, University of Padua, Padua, Italy
| | - Arti Ahluwalia
- Centro Interdipartimentale di Ricerca ″E.Piaggio″, University of Pisa, Pisa, Italy
- CNR Institute of Clinical Physiology, Pisa, Italy
- * E-mail:
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Sung JH, Chon JW, Lee MA, Park JK, Woo JT, Park YK. The anti-obesity effect of Lethariella cladonioides in 3T3-L1 cells and obese mice. Nutr Res Pract 2011; 5:503-10. [PMID: 22259674 PMCID: PMC3259292 DOI: 10.4162/nrp.2011.5.6.503] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 11/22/2011] [Accepted: 11/26/2011] [Indexed: 11/04/2022] Open
Abstract
The aim of this study was to investigate whether a water extract of L. cladonioides (LC) has an anti-obesity effect in 3T3-L1 cells and obese mice. Treatment of differentiated 3T3-L1 adipocytes with LC caused a significant increase in glycerol release and reduced the protein expression of the adipogenic transcription factors, PPARγ and C/EBPα. In an animal model, obese mice were artificially induced by a high fat diet for 10 weeks. Experimental groups were treated with LC (100 mg/kg/day) by gavage for the next 10 weeks. At the end of experiment, the body weight of the LC group mice was reduced by 14.2% compared to the high fat diet (HFD) group. The treatment also decreased liver (31.0%), epididymal (18.0%) and retroperitoneal (19.3%) adipose tissue, and kidney (6.7%) weights, respectively, compared with those of the HFD group. LC prevented diet-induced increases in the serum level of TC (22.6%), TG (11.6%), and glucose (35.0%), respectively, compared with the HFD group. However, the HDL-C level was higher in the LC group (26.1%) than the HFD group. The results of this study thus suggest that LC suppressed lipid accumulation and expression of adipogenic transcription factors, and increased the amount of glycerol release. LC also indicated an anti-obese and anti-hyperlipidemic effect.
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Affiliation(s)
- Ju-Hyun Sung
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin, Gyeonggi 446-701, Korea
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Moon HS, Chung CS, Lee HG, Kim TG, Choi YJ, Cho CS. Inhibitory effect of (-)-epigallocatechin-3-gallate on lipid accumulation of 3T3-L1 cells. Obesity (Silver Spring) 2007; 15:2571-82. [PMID: 18070748 DOI: 10.1038/oby.2007.309] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the molecular mechanisms underlying the attenuating effect of (-)-epigallocatechin-3-gallate (EGCG) on proliferation and lipid accumulation of 3T3-L1 cells, with a focus on the duration of EGCG treatment. RESEARCH METHODS AND PROCEDURES Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay and diamidino-2-phenylindole staining. The anti-adipogenic effect of EGCG on 3T3-L1 cells was analyzed by glycerol-3-phosphate dehydrogenase activity and Oil red O staining. Western blot analysis was used to detect adenosine monophosphate-activated protein kinase (AMPK) activation and phosphorylation of its substrate, acetyl-CoA carboxylase (ACC), and expression of insulin (INS) receptor, INS receptor substrate-1 (IRS-1), and adipocyte marker proteins. RESULTS Exposure to EGCG during the early period of adipogenesis (7 days) was sufficient to prevent lipid accumulation. During this period, EGCG greatly decreased expression of the adipocyte marker proteins peroxisome proliferator-activated receptor gamma2 (PPARgamma2) and liver X receptor (LXR)-alpha. Furthermore, EGCG significantly induced generation of reactive oxygen species (ROS), which led to AMPK activation, and these effects were eliminated by N-acetylcysteine (NAC) treatment. Also, EGCG increased the tyrosine phosphorylation of INS receptor and INS-1 with increasing incubation time. In contrast, EGCG treatment did not alter glycerol release in the presence or absence of 2',5'-dideoxyadenosine (DDA), indicating that EGCG had no effect on lipolysis. DISCUSSION Our data demonstrate that EGCG decreased cell viability and inhibited differentiation of 3T3-L1 cells in a manner dependent on the duration of treatment. Also, we showed that inhibition of adipocyte differentiation by EGCG was associated with decreased glycerol-3-phosphate dehydrogenase (GPDH) activity accompanied by a strong inhibition of PPARgamma2-induced transcriptional activity. Furthermore, the inhibition of adipocyte differentiation by EGCG involved generation of ROS and activation of AMPK.
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Affiliation(s)
- Hyun-Seuk Moon
- School of Agricultural Biotechnology, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, 151-921 Seoul, South Korea
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Getty-Kaushik L, Richard AMT, Corkey BE. Glucose-dependent insulin modulation of oscillatory lipolysis in perifused rat adipocytes. ACTA ACUST UNITED AC 2007; 13:2058-65. [PMID: 16421338 DOI: 10.1038/oby.2005.255] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE We showed glucose-dependent lipolytic oscillations in adipocytes that are modulated by free fatty acids (FFAs). We hypothesized that the oscillations are driven by oscillatory glucose metabolism that leads to oscillatory formation of alpha-glycerophosphate (alpha-GP), oscillatory removal of long-chain coenzyme A (LC-CoA) by alpha-GP to form triglycerides, and oscillatory relief of LC-CoA inhibition of triglyceride lipases. This study examined the effect of insulin on this hypothesis. RESEARCH METHODS AND PROCEDURES Samples were collected every minute from perifused rat adipocytes during the basal state followed by insulin (+/-glucose) or isoproterenol (+/-insulin; n = 4 each). RESULTS Insulin caused a significant increase in glycerol release (18%), with a concomitant significant decrease in FFA release (38%). Without glucose, insulin had no effect on glycerol release while still decreasing FFA release (35%). Insulin (5 microU/mL) attenuated the response of lipolysis to isoproterenol (approximately 3-fold increase with isoproterenol vs. 2-fold increase with insulin + isoproterenol). However, 1 mU/mL insulin amplified the lipolytic response ( approximately 5-fold increase in glycerol release with insulin + isoproterenol), with a concomitant increase in FFA reesterification (no increase in FFA release compared with isoproterenol alone). DISCUSSION We interpret these results to be due to insulin's ability to increase glucose uptake and conversion to alpha-GP, thus removing LC-CoA inhibition of triglyceride lipases. While the physiological importance of lipolytic oscillations remains to be determined, we hypothesize that such an oscillation may play an important role in the delivery of FFAs to the liver, beta cells, and other tissues.
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Moon HS, Lee HG, Choi YJ, Kim TG, Cho CS. Proposed mechanisms of (−)-epigallocatechin-3-gallate for anti-obesity. Chem Biol Interact 2007; 167:85-98. [PMID: 17368440 DOI: 10.1016/j.cbi.2007.02.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 02/11/2007] [Accepted: 02/12/2007] [Indexed: 12/28/2022]
Abstract
Green tea catechins (GTCs) are polyphenolic flavonoids formerly called vitamin P. GTCs, especially (-)-epigallocatechin-3-gallate (EGCG), lower the incidence of cancers, collagen-induced arthritis, oxidative stress-induced neurodegenerative diseases, and streptozotocin-induced diabetes. Also, inhibition of adipogenesis by green tea and green tea extract has been demonstrated in cell lines, animal models, and humans. The obesity-preventive effects of green tea and its main constituent EGCG are widely supported by results from epidemiological, cell culture, animal, and clinical studies in the last decade. Studies with adipocyte cell lines and animal models have demonstrated that EGCG inhibits extracellular signal-related kinases (ERK), activates AMP-activated protein kinase (AMPK), modulates adipocyte marker proteins, and down-regulates lipogenic enzymes as well as other potential targets. Also, the catechin components of green tea have been shown to possess anti-carcinogenic properties possibly related to their anti-oxidant activity. In addition, it was shown that dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus. In this review, the biological activities and multiple mechanisms of EGCG in cell lines, animal models, and clinical observations are explained.
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Affiliation(s)
- Hyun-Seuk Moon
- School of Agricultural Biotechnology, Seoul National University, Seoul 151-921, South Korea
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Moon HS, Lee HG, Seo JH, Chung CS, Guo DD, Kim TG, Choi YJ, Cho CS. Leptin-induced matrix metalloproteinase-2 secretion is suppressed by trans-10,cis-12 conjugated linoleic acid. Biochem Biophys Res Commun 2007; 356:955-60. [PMID: 17386921 DOI: 10.1016/j.bbrc.2007.03.068] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Accepted: 03/14/2007] [Indexed: 10/23/2022]
Abstract
It has long been recognized that leptin, a hormone made by adipocytes, is an important circulating signal for the regulation of body weight. In addition, matrix metalloproteinase (MMP), especially MMP-2, an adipocyte-secreted protein which promotes multi-cellular adipose clusters, is up-regulated in obesity. The present study is designed to evaluate whether trans-10,cis-12 conjugated linoleic acid (t-CLA) can suppress leptin-induced MMP-2 secretion in 3T3-L1 cells. The result showed that expressions of adipocyte marker proteins were significantly reduced by t-CLA-treated cultures, but not by linoleic acid (LA)-treated ones. Interestingly, MMP-2 secretion was significantly increased by leptin-treated cultures, thereby leading to accelerate adipocyte differentiation, indicating that MMP-2 was a necessary mediator of adipogenesis. However, increasing concentration of t-CLA significantly reduced leptin-induced MMP-2 secretion and triglyceride (TG) content. These findings provide support for a role for t-CLA in the regulation of metabolism in leptin-induced adipose tissue development.
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Affiliation(s)
- Hyun-Seuk Moon
- School of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea
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Roy A, Parker RS. Dynamic modeling of free fatty acid, glucose, and insulin: an extended "minimal model". Diabetes Technol Ther 2006; 8:617-26. [PMID: 17109593 DOI: 10.1089/dia.2006.8.617] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND The mathematical models for patients with diabetes proposed in the literature since the late 1970s are mainly glucocentric (glucose-based); hence, the contribution of free fatty acid (FFA) metabolism in the body and its glucose-insulin interactions have been largely ignored. However, approximately 90% of the muscle energy is derived from FFA metabolism when the body is at rest. Furthermore, significant interactions exist among FFA, glucose, and insulin. With the long-term goal of developing a closed-loop glucose control system, a model of the major energy-providing substrate dynamics is required. METHODS The Bergman minimal model was extended to include plasma FFA dynamics, and its interaction with glucose and insulin dynamics, with a primary focus on patients with Type 1 diabetes. Differential equations were developed for plasma FFA concentrations and "remote" FFA effects on glucose uptake, as well as "remote" insulin effects on plasma FFA concentrations. Parameters for the model were estimated from experimental data provided in the scientific literature. RESULTS The minimal model was extended in order to capture three major metabolic aspects: the antilipolytic effect of insulin; the lipolytic effect of prolonged hyperglycemia; and the impairing effect of FFA on glucose uptake rate. The dynamic fit of glucose, FFA, and insulin profiles is consistent with published data. CONCLUSIONS The extended minimal model successfully captured the plasma FFA concentration behavior, the plasma insulin and glucose concentrations, and the physiological interactions that exist among these species. This more comprehensive description of energy-providing substrate dynamics may provide a novel simulation test-bed for analysis of patients with insulin dependent diabetes and controller design.
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Affiliation(s)
- Anirban Roy
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
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Moon HS, Lee HG, Seo JH, Chung CS, Kim TG, Kim IY, Lim KW, Seo SJ, Choi YJ, Cho CS. Down-regulation of PPARgamma2-induced adipogenesis by PEGylated conjugated linoleic acid as the pro-drug: Attenuation of lipid accumulation and reduction of apoptosis. Arch Biochem Biophys 2006; 456:19-29. [PMID: 17084379 DOI: 10.1016/j.abb.2006.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/02/2006] [Accepted: 10/03/2006] [Indexed: 10/24/2022]
Abstract
This study is designed to evaluate whether the PEGylated conjugated linoleic acid (PCLA) as the pro-drug can have favorable stability, bioavailability, and anti-adipogenic activity in 3T3-L1 cells for anti-obesity when compared with conjugated linoleic acid (CLA) itself. The CLA was simply coupled to poly(ethylene glycol) (PEG) at the melting state without solvents or catalysts through ester linkages between the carboxylic group of CLA and the hydroxyl group of PEG. To confirm of PCLA as the pro-drug, CLA release from PCLA was investigated by using high-performance liquid chromatographic (HPLC), showing that CLA release from PCLA was almost 90% in a nearly continuous fashion over the next 75h. Apoptosis was promoted by both CLA- and PCLA-treatments with increasing concentrations. However, the level of cell apoptosis induced by PCLA was lower than that induced by CLA owing to the biocompatible and hydrophilic properties of PEG. Moreover, the PCLA decreased glycerol-3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 cells by acting upon major adipocyte marker proteins such as PPARgamma2, C/EBPalpha, and aP2 modulators. Furthermore, either CLA or PCLA stimulated basal, but not isoproterenol-sensitive, lipolysis in our cell model, suggesting that both CLA and PCLA may stimulate lipolysis via hormone sensitive lipase (HSL)-independent mechanisms. These results suggest that the PCLA may prove to be a stable pro-drug to control the deposition of fat in the human body, and that the anti-adipogenic effect of the PCLA on 3T3-L1 cells will offer a challenging approach for anti-obesity.
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Affiliation(s)
- H S Moon
- School of Agricultural Biotechnology, Seoul National University, Seoul 151-921, South Korea
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Abstract
In IDDM or NIDDM, the total plasma cholesterol and triglycerides are usually within normal limits when the blood glucose is controlled. Marked hypertriglyceridemia can develop with loss of glycemic control and is often due to superimposed genetic abnormalities in lipoprotein metabolism. Tight control in IDDM usually reduces LDL and VLDL to normal levels and may raise HDL above the normal range. Low HDL cholesterol and mild to moderate elevations of VLDL triglyceride are common in NIDDM if obesity or proteinuria is also present. Both HDL and LDL may be smaller and more dense and may be enriched with triglyceride as compared with cholesterol. These abnormalities may require weight loss for control. The increased incidence of cardiovascular disease in diabetes is unexplained but is amplified by the well-defined cardiovascular risk factors. The new American Diabetes Association guidelines call for treatment of high triglycerides and LDL cholesterol to be aggressively reduced. Triglycerides should be under 200 mg/dL, are considered borderline high between 200 and 400 mg/dL, and high when above 400 mg/dL. Low HDL is defined as less than 35 mg/dL. Control of obesity with diet and exercise and reduced intake of saturated fat and cholesterol are important first steps. If needed, drug therapy is appropriate to reduce LDL to levels below 130 mg/dL in all adult diabetics and below 100 mg/dL in those with cardiovascular disease.
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Affiliation(s)
- W V Brown
- Division of Arteriosclerosis and Lipid Metabolism, Emory University School of Medicine, Atlanta, Georgia
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Rizkalla SW, Luo J, Guilhem I, Boillot J, Bruzzo F, Chevalier A, Slama G. Comparative effects of 6 week fructose, dextrose and starch feeding on fat-cell lipolysis in normal rats: effects of isoproterenol, theophylline and insulin. Mol Cell Biochem 1992; 109:127-32. [PMID: 1625679 DOI: 10.1007/bf00229766] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The precise effects of fructose feeding on adipose tissue is not clearly known. Consequently, we studied the effects of fructose feeding on stimulated and inhibited in vitro lipolysis. Twenty seven male Sprague Dawley rats, 5 weeks of age, were fed for 6 weeks on one of three diets containing 57% CHO as fructose (F), dextrose (D) or starch (S). At week 6 the epididymal fat pad weights showed no difference between groups. Stimulation of lipolysis by isoproterenol or theophylline showed: decreased sensitivity of adipocytes to isoproterenol, but not to theophylline, in F (p less than 0.05); the maximal responses were decreased, but NS, after stimulation by either isoproterenol or theophylline. The maximal antilipolytic responses to insulin were increased in F (27%) and D (29%) when compared to S (16%), (p less than 0.05). Only, in F there was an increase (NS) in ED50 (0.63 +/- 0.23 ng/ml) compared to D (0.45 +/- 0.18) and S (0.29 +/- 0.18), indicating decreased sensitivity. Nonfasting plasma insulin and triglycerides were increased at the 6th week in F (p less than 0.01), without any change in plasma glucose levels. However, there was no difference in 12 h fasting plasma glucose, insulin or triglycerides. In conclusion, a 6 week 57% fructose containing diet in normal rats led to: 1) decreased lipid mobilization in the epididymal adipose tissue; and 2) increased nonfasting plasma insulin and triglycerides. Thus fructose, under these experimental conditions, seems to have adverse metabolic effects in normal rats.
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Affiliation(s)
- S W Rizkalla
- Department of Diabetes, INSERM U 341, Hôtel-Dieu Hospital, Paris, France
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Carlson MG, Snead WL, Hill JO, Nurjhan N, Campbell PJ. Glucose regulation of lipid metabolism in humans. THE AMERICAN JOURNAL OF PHYSIOLOGY 1991; 261:E815-20. [PMID: 1767842 DOI: 10.1152/ajpendo.1991.261.6.e815] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The role of plasma glucose in the regulation of lipid metabolism in humans, independent of associated changes in hormone concentrations, is controversial. Therefore we examined the role of glucose in the regulation of lipolysis and free fatty acid (FFA) reesterification in six healthy lean male volunteers. Blood glucose concentration was clamped at either 5 or 10 mM during 2-h pancreatic-pituitary clamps. Glycerol and palmitate turnover were measured by isotope dilution ([1-14C]palmitate and [2H5]-glycerol). All hormone concentrations were the same during the euglycemic and hyperglycemic studies. FFA turnover, which represents the difference between lipolysis and FFA reesterification, was reduced 30% by hyperglycemia (29 +/- 2 vs. 20 +/- 3 mumol.kg fat mass-1.min-1, P less than 0.05). Glycerol turnover, which represents lipolysis only, was reduced to a similar extent (9.4 +/- 0.9 vs. 6.2 +/- 0.7 mumol.kg fat mass-1.min-1, P less than 0.05). We conclude that glucose regulates lipid metabolism, independently of changes in hormone concentrations. The equivalent suppression of glycerol and FFA turnover indicates that the effect is mediated by suppression of lipolysis and not by stimulation of FFA reesterification.
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Affiliation(s)
- M G Carlson
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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