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Tejero ME, Freeland-Graves JH, Proffitt JM, Peebles KW, Cai G, Cole SA, Comuzzie AG. Adiponectin But Not Resistin Is Associated with Insulin Resistance-Related Phenotypes in Baboons. ACTA ACUST UNITED AC 2012; 12:871-7. [PMID: 15166309 DOI: 10.1038/oby.2004.105] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE The hormones adiponectin and resistin have been associated with insulin resistance. This paper analyzed the potential relationship between adiponectin and resistin and insulin resistance-related phenotypes in baboons. RESEARCH METHODS AND PROCEDURES One hundred eight adult baboons (84 female and 24 male) were studied. Weight was measured, and a blood sample was collected under fasting conditions for plasma and monocyte isolation. Fasting glucose, insulin, C-peptide, and adiponectin levels in plasma were measured by standard methods. Insulin resistance was calculated by the homeostasis model assessment index. Resistin mRNA abundance in monocytes was determined by real-time quantitative reverse transcription-polymerase chain reaction. Data were clustered by weight tertiles for statistical analysis. RESULTS As observed in humans, the insulin resistance-related phenotypes were related to weight, plasma levels of adiponectin, and C-peptide. No significant relationship between resistin circulating levels or expression in monocytes and insulin resistance-related phenotypes was found in baboons. DISCUSSION These findings suggest that resistin is not associated with insulin resistance. However, previous observations of relationships among weight, adiponectin, and insulin resistance are confirmed.
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Gui Y, Silha JV, Murphy LJ. Sexual Dimorphism and Regulation of Resistin, Adiponectin, and Leptin Expression in the Mouse. ACTA ACUST UNITED AC 2012; 12:1481-91. [PMID: 15483213 DOI: 10.1038/oby.2004.185] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To examine gender differences and hormonal regulation of resistin, adiponectin, and leptin. RESEARCH METHODS AND PROCEDURES Plasma levels were measured, and mRNA expression in perigonadal fat was quantified by RNase protection assays. RESULTS Plasma resistin declined with age despite an increase in adiposity in both genders. In male mice, plasma leptin increased, whereas adiponectin levels were constant. In females, both adiponectin and leptin levels increased with age. Resistin mRNA levels were significantly higher in female than male mice at all ages, whereas leptin and adiponectin mRNA levels were similar in fat from 6-week-old male and female mice, and sexual dimorphism was apparent only in the older mice, with higher levels apparent in females. Castration did not abolish gender differences in plasma levels or resistin, adiponectin, or leptin mRNAs. Castration of male mice did not significantly change adipokine mRNA levels or plasma levels of resistin or leptin; however, adiponectin was significantly increased. Dihydrotestosterone treatment had no effect on adipokine mRNA expression or resistin and adiponectin levels but increased leptin levels. In contrast, ovariectomy significantly increased resistin mRNA abundance and decreased leptin and adiponectin mRNAs. Plasma leptin levels were also increased by ovariectomy, whereas resistin and adiponectin levels were unchanged. Estrogen replacement significantly reduced resistin mRNA and increased leptin and adiponectin mRNA levels but had no effect on plasma adipokine levels. DISCUSSION The gender differences in adipokine mRNA expression and plasma levels were not ablated by castration and seem to be dependent on other factors in addition to gonadal steroids.
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Wen S, Felley CP, Kessler V, Michetti P, Pan-Hammarström Q. Comment on "Resistin-like molecule beta (RELMbeta/FIZZ2) is highly expressed in the ileum of SAMP1/YitFc mice and is associated with initiation of ileitis". THE JOURNAL OF IMMUNOLOGY 2008; 180:2009; author reply 2009-10. [PMID: 18250402 DOI: 10.4049/jimmunol.180.4.2009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Fujio J, Kushiyama A, Sakoda H, Fujishiro M, Ogihara T, Fukushima Y, Anai M, Horike N, Kamata H, Uchijima Y, Kurihara H, Asano T. Regulation of gut-derived resistin-like molecule beta expression by nutrients. Diabetes Res Clin Pract 2008; 79:2-10. [PMID: 17936398 DOI: 10.1016/j.diabres.2007.04.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 02/19/2007] [Accepted: 04/16/2007] [Indexed: 11/21/2022]
Abstract
Resistin was initially identified as a protein, secreted by adipocytes, which inhibits insulin action and adipose differentiation. The three proteins homologous to resistin were identified and given the names resistin-like molecules (RELM) alpha, beta and gamma. Resistin and RELMalpha are abundantly expressed in adipose, but RELMbeta and RELMgamma are secreted mainly from the gut. Since nutrient composition greatly affects insulin sensitivity, we investigated the regulatory effects of various nutritional factors in food on the expressions of resistin family proteins. First, mice were given diets with different nutritional compositions (high-carbohydrate, high-protein and high-fat) for 2 weeks. RELMbeta mRNA expression in the intestines was markedly suppressed by the high-protein and high-carbohydrate diets, while slightly but not significantly upregulated by the high-fat diet. In the epididymal fat, resistin expression was unchanged, while RELMalpha expression was markedly decreased by the high-carbohydrate diet. Taking into consideration that humans have neither RELMalpha nor RELMgamma, our subsequent studies focused on RELMbeta expression. We used the human colon cancer cell line LS174T. Treatments with insulin and TNFalpha as well as stearic acid, a saturated free fatty acid, upregulated RELMbeta expression, while d-glucose downregulated RELMbeta. These results suggest RELMbeta expression to be regulated directly by nutrients such as glucose and saturated free fatty acids including stearic acid, as well as by hormones including insulin and TNFalpha. These regulations may play an important role in the nutrient-associated induction of insulin resistance.
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Mishra A, Wang M, Schlotman J, Nikolaidis NM, DeBrosse CW, Karow ML, Rothenberg ME. Resistin-like molecule-beta is an allergen-induced cytokine with inflammatory and remodeling activity in the murine lung. Am J Physiol Lung Cell Mol Physiol 2007; 293:L305-13. [PMID: 17545488 DOI: 10.1152/ajplung.00147.2007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Resistin-like molecule (RELM)-beta is a cysteine-rich cytokine implicated in insulin resistance and asthmatic responses, but its function remains an enigma. We now report that RELM-beta has a role in promoting airway inflammation and lung remodeling in the mouse lung. RELM-beta is strongly induced by diverse allergens and T helper type 2 (Th2) cytokines by an IL-13- and STAT6-dependent mechanism. To understand the in vivo role of RELM-beta, we delivered recombinant murine RELM-beta intratracheally to naïve mice. RELM-beta induced dose-dependent leukocyte accumulation (most prominently involving macrophages) and goblet cell hyperplasia. The most prominent effect induced by RELM-beta was increased perivascular and peribronchial collagen deposition. Mice genetically deficient in RELM-beta had reduced accumulation of collagen and goblet cell hyperplasia in an experimental model of allergic airway inflammation. In vitro experiments demonstrated that RELM-beta had fibroblast motogenic activity. These results identify RELM-beta as a Th2-associated cytokine with potent inflammatory and remodeling activity.
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McVay LD, Keilbaugh SA, Wong TM, Kierstein S, Shin ME, Lehrke M, Lefterova MI, Shifflett DE, Barnes SL, Cominelli F, Cohn SM, Hecht G, Lazar MA, Haczku A, Wu GD. Absence of bacterially induced RELMbeta reduces injury in the dextran sodium sulfate model of colitis. J Clin Invest 2006; 116:2914-23. [PMID: 17024245 PMCID: PMC1590268 DOI: 10.1172/jci28121] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 08/15/2006] [Indexed: 12/15/2022] Open
Abstract
Although inflammatory bowel disease (IBD) is the result of a dysregulated immune response to commensal gut bacteria in genetically predisposed individuals, the mechanism(s) by which bacteria lead to the development of IBD are unknown. Interestingly, deletion of intestinal goblet cells protects against intestinal injury, suggesting that this epithelial cell lineage may produce molecules that exacerbate IBD. We previously reported that resistin-like molecule beta (RELMbeta; also known as FIZZ2) is an intestinal goblet cell-specific protein that is induced upon bacterial colonization whereupon it is expressed in the ileum and colon, regions of the gut most often involved in IBD. Herein, we show that disruption of this gene reduces the severity of colitis in the dextran sodium sulfate (DSS) model of murine colonic injury. Although RELMbeta does not alter colonic epithelial proliferation or barrier function, we show that recombinant protein activates macrophages to produce TNF-alpha both in vitro and in vivo. RELMbeta expression is also strongly induced in the terminal ileum of the SAMP1/Fc model of IBD. These results suggest a model whereby the loss of epithelial barrier function by DSS results in the activation of the innate mucosal response by RELMbeta located in the lumen, supporting the hypothesis that this protein is a link among goblet cells, commensal bacteria, and the pathogenesis of IBD.
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Yamauchi J, Kawai Y, Yamada M, Uchikawa R, Tegoshi T, Arizono N. Altered expression of goblet cell- and mucin glycosylation-related genes in the intestinal epithelium during infection with the nematode Nippostrongylus brasiliensis in rat. APMIS 2006; 114:270-8. [PMID: 16689826 DOI: 10.1111/j.1600-0463.2006.apm_353.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Intestinal nematode infection induces marked goblet cell hyperplasia and mucus secretion, but the mechanisms of regulation of the changes still remain to be elucidated. In the present study, epithelial cells were isolated from the rat small intestine at various times after Nippostrongylus brasiliensis infection, and the levels of expression of goblet cell- and mucin glycosylation-related genes were estimated by semi-quantitative reverse transcription (RT)-PCR. Among the genes investigated, mucin core peptide (MUC) 2, sialyltransferase (Siat) 4c and trefoil factor family (TFF) 3 were upregulated as early as 2-4 days post-infection, suggesting that they are associated with an early innate protective response. Seven days post-infection and thereafter, when the nematodes reached maturity, significant upregulation of MUC3, MUC4, resistin-like molecule beta (Relmbeta) and 3O-sulfotransferase (3ST)1 was observed, while 3ST2 expression levels increased after the majority of the worms were expelled from the intestine. Similar alterations of glycosylation-related gene expression were also observed in mast-cell-deficient Ws/Ws rats, suggesting that mast cells in the epithelium are not relevant to the upregulation of these genes. The present finding that the expression level of each goblet cell- or glycosylation-related gene was altered differently during the time course of infection indicates the progression of sequential qualitative changes in the mucus layer after infection.
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Ohashi A, Matsushita Y, Kimura K, Miyashita K, Saito M. Conjugated linoleic acid deteriorates insulin resistance in obese/diabetic mice in association with decreased production of adiponectin and leptin. J Nutr Sci Vitaminol (Tokyo) 2005; 50:416-21. [PMID: 15895517 DOI: 10.3177/jnsv.50.416] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dietary supplementation of conjugated linoleic acids (CLA) is known to have some beneficial effects such as anti-carcinogenic and anti-obesity effects in several animal species, while it also induces insulin resistance and fatty liver, especially in mice. To explore the possible factors responsible for the CLA-induced insulin resistance, we examined the plasma and mRNA expression levels of several adipocytokines, which are likely involved in the regulation of insulin sensitivity, in normal C5 7BL, mildly obese/diabetic KK and morbidly obese/diabetic KKAy mice. Feeding a diet supplemented with 0.5%, CLA oil consisting of 30.5/% c9, t11-CLA and 28.9% t10, c12-CLA for 4 wk resulted in a decrease in white adipose tissue (WAT), an increase in liver weight with excess accumulation of triglyceride, and insulin resistance associated with hyperglycemia and hyperinsulinemia. The plasma and WAT mRNA levels of leptin were higher in KK and KKAy mice than C57BI. mice, whereas those of adiponectin were higher in C5 7BL mice. CLA-feeding decreased the levels of leptin, adiponectin and resistin, especially in KK and KKAy mice. In contrast, tumor necrosis factor-alpha (TNFalpha) mRNA levels were higher in KK and KKAy mice than C57BL mice, and were increased by CLA feeding. The present results thus indicate that CLA feeding promotes insulin resistance in obese/diabetic mice by at least inverse regulation of leptin and adiponectin, and TNFalpha, adipocytokines known to either ameliorate or deteriorate insulin sensitivity, respectively.
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Osawa H, Onuma H, Ochi M, Murakami A, Yamauchi J, Takasuka T, Tanabe F, Shimizu I, Kato K, Nishida W, Yamada K, Tabara Y, Yasukawa M, Fujii Y, Ohashi J, Miki T, Makino H. Resistin SNP-420 determines its monocyte mRNA and serum levels inducing type 2 diabetes. Biochem Biophys Res Commun 2005; 335:596-602. [PMID: 16087164 DOI: 10.1016/j.bbrc.2005.07.122] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Accepted: 07/22/2005] [Indexed: 12/13/2022]
Abstract
Resistin, secreted from adipocytes, causes insulin resistance in rodents. Its roles and main source in humans remain unknown. The G/G genotype of resistin single nucleotide polymorphism, SNP-420, induces type 2 diabetes mellitus (T2DM) by increasing promoter activity. We elucidated factors correlated with serum resistin and effects of SNP-420 on monocyte resistin mRNA. In 198 T2DM and 157 controls, fasting serum resistin was higher in T2DM. Multiple regression analysis revealed that SNP-420 genotype was the strongest determinant of serum resistin. In T2DM, 1-year duration of T2DM and 1% HbA1c was also correlated with 0.19 and 0.54 ng/ml serum resistin, respectively. Logistic regression analysis revealed that serum resistin was an independent factor for T2DM. In 23 healthy volunteers, monocyte resistin mRNA was positively correlated with its simultaneous serum levels and was higher in G/G genotype. Thus, SNP-420 determines monocyte mRNA and serum levels of resistin, which could induce T2DM.
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MESH Headings
- Adipocytes/metabolism
- Adult
- Aged
- Case-Control Studies
- DNA/metabolism
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/genetics
- Female
- Genotype
- Hormones, Ectopic/blood
- Hormones, Ectopic/genetics
- Hormones, Ectopic/metabolism
- Humans
- Insulin Resistance
- Male
- Middle Aged
- Monocytes/metabolism
- Polymorphism, Genetic
- Polymorphism, Single Nucleotide
- Promoter Regions, Genetic
- RNA, Messenger/metabolism
- Regression Analysis
- Resistin
- Sequence Analysis, DNA
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Pagano C, Marin O, Calcagno A, Schiappelli P, Pilon C, Milan G, Bertelli M, Fanin E, Andrighetto G, Federspil G, Vettor R. Increased serum resistin in adults with prader-willi syndrome is related to obesity and not to insulin resistance. J Clin Endocrinol Metab 2005; 90:4335-40. [PMID: 15870134 DOI: 10.1210/jc.2005-0293] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CONTEXT Determinants of insulin resistance in Prader-Willi syndrome (PWS) are not completely understood. The discovery of several adipokines with relevant effects on insulin resistance and cardiovascular complications of metabolic syndrome offered new tools of investigation of insulin resistance in PWS. OBJECTIVE The purpose of this study was to measure serum resistin and mRNA in adipose tissue of patients with PWS, those with simple obesity, and healthy controls and correlate resistin levels with anthropometric and biochemical features. DESIGN Twenty-eight adult PWS patients, 29 obese patients, and 25 healthy controls were studied. Anthropometric variables were measured and fasting serum and plasma were collected for measurement of resistin, adiponectin, leptin, lipid profile, glucose, and insulin. RESULTS Serum resistin and resistin mRNA expression in adipose tissue was significantly higher in PWS patients, compared with both healthy lean controls and obese patients. Moreover, on regression analysis resistin was significantly correlated with body mass index, whereas no significant association was found between resistin and homeostasis model assessment index. A weak association between resistin and adiponectin was found in the PWS group only. However, on multivariate analysis only the correlation between resistin and body mass index remained significant. CONCLUSIONS These results support a link between circulating resistin and obesity in humans but do not support a role for resistin in human insulin resistance.
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Saravanan N, Haseeb A, Ehtesham NZ. Differential effects of dietary saturated and trans-fatty acids on expression of genes associated with insulin sensitivity in rat adipose tissue. Eur J Endocrinol 2005; 153:159-65. [PMID: 15998628 DOI: 10.1530/eje.1.01946] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Trans-fatty acids (TFAs) are formed during partial hydrogenation of vegetable oils and are shown to be more atherogenic than saturated fatty acids (SFAs). Our previous study showed that dietary TFAs decrease adipose tissue insulin sensitivity to a greater extent than SFAs in rats. We hypothesized that the effects of these fatty acids on insulin sensitivity could be mediated through an alteration in gene expression. In the current study we have investigated the effects of dietary TFAs or SFAs on expression of genes associated with insulin sensitivity in rat adipose tissue. DESIGN AND METHODS Male weanling Wistar/NIN rats were divided into four groups and fed one of the following diets containing 10% fat (g/100 g diet) differing only in the fatty acid composition for 3 months: control diet (3.7% linoleic acid (LA)), SFA diet (5% SFA), TFA diet 1 (1.5% TFA + 1% LA) and TFA diet 2 (1.5% TFA + 2% LA). The mRNA expression of peroxisome proliferator-activated receptor gamma (PPARgamma), lipoprotein lipase (LPL), glucose transporter-4 (GLUT4), resistin and adiponectin was analyzed in epididymal fat using RT-PCR. The effects of TFA were studied at two levels of LA to understand the beneficial effects of LA over the effects of TFA. RESULTS Both dietary SFA and TFA upregulated the mRNA levels of resistin. Dietary SFA downregulated adiponectin and GLUT4 and upregulated LPL, while TFA downregulated PPARgamma and LPL. The effects of dietary TFA on PPARgamma and resistin were not counteracted by increased LA (TFA diet 2). CONCLUSION The effects of SFAs on the aforementioned genes except PPARgamma could be extrapolated towards decreased insulin sensitivity, while only the alteration in the mRNA levels of PPARgamma and resistin could be associated with insulin resistance in TFA-fed rats. These findings suggest that dietary SFAs and TFAs alter the expression of different genes associated with insulin sensitivity in adipose tissue.
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Graveleau C, Zaha VG, Mohajer A, Banerjee RR, Dudley-Rucker N, Steppan CM, Rajala MW, Scherer PE, Ahima RS, Lazar MA, Abel ED. Mouse and human resistins impair glucose transport in primary mouse cardiomyocytes, and oligomerization is required for this biological action. J Biol Chem 2005; 280:31679-85. [PMID: 15983036 DOI: 10.1074/jbc.m504008200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The adipocytokine resistin impairs glucose tolerance and insulin sensitivity in rodents. Here, we examined the effect of resistin on glucose uptake in isolated adult mouse cardiomyocytes. Murine resistin reduced insulin-stimulated glucose uptake, establishing the heart as a resistin target tissue. Notably, human resistin also impaired insulin action in mouse cardiomyocytes, providing the first evidence that human and mouse resistin homologs have similar functions. Resistin is a cysteine-rich molecule that circulates as a multimer of a dimeric form dependent upon a single intermolecular disulfide bond, which, in the mouse, involves Cys26; mutation of this residue to alanine (C26A) produces a monomeric molecule that appears to be bioactive in the liver. Remarkably, unlike native resistin, monomeric C26A resistin had no effect on basal or insulin-stimulated glucose uptake in mouse cardiomyocytes. Resistin impairs glucose uptake in cardiomyocytes by mechanisms that involve altered vesicle trafficking. Thus, in cardiomyocytes, both mouse and human resistins directly impair glucose transport; and in contrast to effects on the liver, these actions of resistin require oligomerization.
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Tejero ME, Cole SA, Cai G, Peebles KW, Freeland-Graves JH, Cox LA, Mahaney MC, Rogers J, VandeBerg JL, Blangero J, Comuzzie AG. Genome-wide scan of resistin mRNA expression in omental adipose tissue of baboons. Int J Obes (Lond) 2005; 29:406-12. [PMID: 15326464 DOI: 10.1038/sj.ijo.0802699] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION The hormone resistin was recently discovered in adipose tissue of mice. Functional tests suggest a role for resistin in the regulation of insulin sensitivity. However, human studies have reported controversial results on the metabolic function of this hormone. METHODS A 1 g omental adipose tissue biopsy was obtained from 404 adult baboons. Resistin mRNA expression was assayed by real-time, quantitative RT-PCR, and univariate and bivariate quantitative genetic analyses were performed, via the variance decomposition approach. A genome scan analysis was conducted using resistin mRNA abundance in omental adipose tissue as a quantitative phenotype. RESULTS A significant heritability of h2 = 0.23 (P = 0.003) was found for resistin mRNA abundance in omental adipose tissue. A genome scan detected a quantitative trait locus for resistin expression with an LOD score of 3.8, in the region between markers D19S431 and D19S714, corresponding to human chromosome 19 p13. This chromosomal region contains genes related to insulin resistance phenotypes, such as resistin, insulin receptor, angiopoietin-like 4 protein and LDL receptor. CONCLUSIONS Individual variation in resistin mRNA expression has a significant genetic component, and a gene or genes on chromosome 19 p13 may regulate resistin mRNA levels in baboon omental adipose tissue.
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Caja S, Martínez I, Abelenda M, Puerta M. Resistin expression and plasma concentration peak at different times during pregnancy in rats. J Endocrinol 2005; 185:551-9. [PMID: 15930181 DOI: 10.1677/joe.1.05932] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Resistin has been proposed as both an anti-adipogenic factor and an inducer of insulin resistance. During late pregnancy, white adipose tissue mass increases and insulin sensitivity decreases. To check for the involvement of resistin in these processes, we measured plasma resistin in pregnant and non-pregnant rats and in lactating dams. Plasma resistin increased by day 15 of pregnancy and remained high 5 days post partum. The simultaneous increase in plasma resistin concentration and the decrease in insulin sensitivity is compatible with resistin depressing maternal insulin sensitivity. Resistin expression increased 5-15 times in visceral white adipose tissue depots by day 8 of pregnancy but was similar to pre-pregnancy values by day 19. Resistin expression in the placenta and mammary gland was similar to that in the parametrial adipose depot by day 8 but was almost null by day 19. There was therefore a time-lag between the peaks in expression and in plasma concentration. White adipose tissue mass increased without changes in adipocyte size once peaks in resistin expression had passed, which is compatible with an anti-adipogenic role for enhanced resistin expression. A bolus injection of chorionic gonadotrophin - which peaks in early pregnancy - to non-pregnant rats increased resistin expression in white adipose tissue, indicating that this hormone is involved in controlling resistin expression. Resistin was not detected in cerebrospinal fluid. Our results have suggested a role for resistin in pregnancy.
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Chung SS, Choi HH, Kim KW, Cho YM, Lee HK, Park KS. Regulation of human resistin gene expression in cell systems: an important role of stimulatory protein 1 interaction with a common promoter polymorphic site. Diabetologia 2005; 48:1150-8. [PMID: 15864531 DOI: 10.1007/s00125-005-1762-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Accepted: 01/20/2005] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS Resistin is an adipokine that might link obesity and insulin resistance. A common polymorphism of the human resistin gene, -420C >G, is a major determinant of plasma resistin concentrations as well as resistin mRNA expression in human adipose tissue. In this study, we investigated the regulatory mechanism by which this polymorphism affects resistin expression. METHODS Electrophoretic mobility shift assay was performed to identify the transcription factors binding to the -420G region. Transient transfection and reporter assay were used to measure promoter activities of the resistin gene. The binding ability of stimulatory protein 1 (Sp1) in response to adipocyte differentiation or high glucose concentrations was also measured. RESULTS Sp1 and stimulatory protein 3 (Sp3) specifically bound to the region around -420G of the human resistin gene. Overexpression of Sp1 increased the promoter activity regardless of -420 genotypes, while the promoter activity of the -420G construct was two-fold higher than that of the -420C construct. In contrast, overexpression of Sp3 scarcely increased the promoter activity. The binding ability of Sp1 to the -420G region was increased in response to adipocyte differentiation. Mithramycin A, an inhibitor of DNA binding of Sp1, reduced the effect of high glucose on transcription induction of the resistin gene in adipocytes. CONCLUSIONS/INTERPRETATION These results suggest that Sp1 is an important factor regulating transcription of human resistin gene. A common polymorphism of the human resistin promoter, -420C >G, is critical for the binding of Sp1 and modulates the transcriptional activity of the resistin gene by changing the binding ability of Sp1. In addition, Sp1 may be involved in the increase of resistin expression by hyperglycaemia.
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Kunnari A, Ukkola O, Kesäniemi YA. Resistin polymorphisms are associated with cerebrovascular disease in Finnish Type 2 diabetic patients. Diabet Med 2005; 22:583-9. [PMID: 15842513 DOI: 10.1111/j.1464-5491.2005.01480.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS Resistin is a hormone secreted by adipocytes and it is also expressed in monocytes. Resistin has been found to increase insulin resistance, a key feature in Type 2 diabetes. The aim of this study was to investigate whether resistin polymorphisms are associated with Type 2 diabetes and its clinical characteristics. METHODS We studied the allele and genotype frequencies of the single-nucleotide polymorphisms (SNPs)-420 (C>G), +157 (T>C) and +299 (G>A) in the resistin gene in 258 Finnish Type 2 diabetics and 494 controls. RESULTS These three markers were in significant linkage disequilibrium with each other. No significant (P<0.05) differences in the allele or genotype frequencies were observed between the study groups. Subjects with Type 2 diabetes showed a significant association between cerebrovascular disease and the SNPs-420 (P=0.004) and +299 (P=0.007), the G-G and A-A genotypes, respectively, had the highest frequencies. SNPs-420 (P=0.000) and +299 (P=0.002) in men and SNP+157 in men (P=0.005) and in women (P=0.019) showed significant association with higher mean blood glucose. The rare allele homozygotes also had the highest mean blood glucose values. We also observed associations between at least one of the SNPs and fasting blood glucose, glycosylated haemoglobin A1 (GHbA1), low-density lipoprotein (LDL) cholesterol and systolic and diastolic blood pressure. After correction for multiple comparisons, the association between the promoter variant SNP-420 and cerebrovascular disease in both genders and the associations between mean blood glucose and SNP-420 and SNP+299 in men remained significant. CONCLUSIONS The results suggest that resistin may play a role in atherogenesis probably through increasing insulin resistance.
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Shojima N, Ogihara T, Inukai K, Fujishiro M, Sakoda H, Kushiyama A, Katagiri H, Anai M, Ono H, Fukushima Y, Horike N, Viana AYI, Uchijima Y, Kurihara H, Asano T. Serum concentrations of resistin-like molecules beta and gamma are elevated in high-fat-fed and obese db/db mice, with increased production in the intestinal tract and bone marrow. Diabetologia 2005; 48:984-92. [PMID: 15834545 DOI: 10.1007/s00125-005-1735-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Accepted: 12/03/2004] [Indexed: 11/28/2022]
Abstract
AIMS/HYPOTHESIS Resistin and the resistin-like molecules (RELMs) comprise a novel class of cysteine-rich proteins. Among the RELMs, RELMbeta and RELMgamma are produced in non-adipocyte tissues, but the regulation of their expression and their physiological roles are largely unknown. We investigated in mice the tissue distribution and dimer formation of RELMbeta and RELMgamma and then examined whether their serum concentrations and tissue expression levels are related to insulin resistance. METHODS Specific antibodies against RELMbeta and RELMgamma were generated. Dimer formation was examined using COS cells and the colon. RELMbeta and RELMgamma tissue localisation and expression levels were analysed by an RNase protection assay, immunoblotting and immunohistochemical study. Serum concentrations in high-fat-fed and db/db mice were also measured using the specific antibodies. RESULTS The intestinal tract produces RELMbeta and RELMgamma, and colonic epithelial cells in particular express both RELMbeta and RELMgamma. In addition, RELMbeta and RELMgamma were shown to form a homodimer and a heterodimer with each other, in an overexpression system using cultured cells, and in mouse colon and serum. Serum RELMbeta and RELMgamma levels in high-fat-fed mice were markedly higher than those in mice fed normal chow. Serum RELMbeta and RELMgamma concentrations were also clearly higher in db/db mice than in lean littermates. Tissue expression levels revealed that elevated serum concentrations of RELMbeta and RELMgamma are attributable to increased production in the colon and bone marrow. CONCLUSIONS/INTERPRETATION RELMbeta and RELMgamma form homo/heterodimers, which are secreted into the circulation. Serum concentrations of RELMbeta and RELMgamma may be a novel intestinal-tract-mediating regulator of insulin sensitivity, possibly involved in insulin resistance induced by obesity and a high-fat diet.
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Cettour-Rose P, Theander-Carrillo C, Asensio C, Klein M, Visser TJ, Burger AG, Meier CA, Rohner-Jeanrenaud F. Hypothyroidism in rats decreases peripheral glucose utilisation, a defect partially corrected by central leptin infusion. Diabetologia 2005; 48:624-33. [PMID: 15756538 DOI: 10.1007/s00125-005-1696-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Accepted: 12/13/2004] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS The aims of this work were to determine the effect of hypothyroidism on insulin-stimulated glucose turnover and to unravel the potential mechanisms involved in such an effect. METHODS Hypothyroidism was induced by administration of propylthiouracil, with partial T4 substitution. Euglycaemic-hyperinsulinaemic clamps, associated with the labelled 2-deoxy-D-glucose technique for measuring tissue-specific glucose utilisation, were used. To assess a possible involvement of leptin in the modulation of glucose metabolism by hypothyroidism, leptin was infused intracerebroventricularly for 6 days. A group of leptin-infused rats was treated with rT3 to determine a potential role of T3 in mediating the leptin effects. RESULTS Compared with euthyroid rats, hypothyroid animals exhibited decreased overall glucose turnover and decreased glucose utilisation indices in skeletal muscle and adipose tissue. Leptinaemia in hypothyroid rats was lower while resistin mRNA expression in adipose tissue was higher than in euthyroid animals. Intracerebroventricular leptin infusion in hypothyroid rats partially restored overall, muscle and adipose tissue insulin-stimulated glucose utilisation and improved the reduced glycaemic response observed during insulin tolerance tests. The leptin effects were due neither to the observed increase in plasma T3 levels nor to changes in the high adipose tissue resistin expression of hypothyroid rats. The administration of leptin to hypothyroid animals was accompanied by increased expression of muscle and adipose tissue carnitine palmitoyl transferases, decreased plasma NEFA levels and reduced muscle triglyceride content. CONCLUSIONS/INTERPRETATION Hypothyroidism is characterised by decreased insulin responsiveness, partly mediated by an exaggerated glucose-fatty acid cycle that is partly alleviated by intracerebroventricular leptin administration.
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Lin SY, Sheu WHH, Chen WY, Lee FY, Huang CJ. Stimulated resistin expression in white adipose of rats with bile duct ligation-induced liver cirrhosis: relationship to cirrhotic hyperinsulinemia and increased tumor necrosis factor-alpha. Mol Cell Endocrinol 2005; 232:1-8. [PMID: 15737463 DOI: 10.1016/j.mce.2005.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 01/14/2005] [Accepted: 01/18/2005] [Indexed: 02/07/2023]
Abstract
Resistin, an adipose-derived polypeptide hormone, is proposed as a candidate of insulin resistance, although its roles in inhibiting adipogenesis and in inflammation have also been suggested. Liver cirrhosis is characterized by elevated circulating proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), hyperinsulinemia and insulin resistance. The study aimed to examine resistin expression and its association with insulin and TNF-alpha in a cirrhotic rat model using bile duct ligation (BDL). The BDL-induced cirrhotic rats showed significantly lower fat mass, insulin sensitivity and elevated plasma insulin and TNF-alpha compared to sham animals. In addition, epididymal TNF-alpha and resistin mRNA and protein levels were higher in cirrhotic rats. In normal control rats, in vivo insulin infusion and ex vivo administration of TNF-alpha to cultured fat pads increased resistin gene expression significantly. These results implied that hyperinsulinemia and increased TNF-alpha levels might upregulate adipose resistin gene in BDL-induced liver cirrhosis. Further study is necessary to document the role of resistin in metabolic abnormalities of liver cirrhosis.
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20
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Lee JH, Bullen JW, Stoyneva VL, Mantzoros CS. Circulating resistin in lean, obese, and insulin-resistant mouse models: lack of association with insulinemia and glycemia. Am J Physiol Endocrinol Metab 2005; 288:E625-32. [PMID: 15522996 DOI: 10.1152/ajpendo.00184.2004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Resistin is an adipocyte-secreted hormone proposed to link obesity with insulin resistance and diabetes, but no previous study has performed a joint quantitative evaluation of white adipose tissue (WAT) resistin mRNA expression and serum levels in relation to insulinemia and glycemia in mice. We have thus comparatively assessed WAT resistin mRNA expression and serum resistin levels in lean C57BL/6J mice and various mouse models of obesity, including diet-induced obese (DIO) C57BL/6J mice, high fat-fed TNF-alpha-/- mice, and brown adipose tissue (BAT)-deficient uncoupling protein-diphtheria toxin A chain (UCP1-DTA) mice. We also studied whether treatment with the weight-reducing and insulin-sensitizing compounds, MTII, an alpha-melanocyte-stimulating hormone analog, or CNTF(Ax15), a ciliary neurotrophic factor analog, alters resistin mRNA expression and/or circulating levels in lean and DIO C57BL/6J mice. We find that resistin mRNA expression is similar in DIO and lean C57BL/6J mice, as well as in TNF-alpha-/- and wild-type (WT) mice. Circulating resistin levels, however, are higher in DIO C57BL/6J, high fat-fed TNF-alpha-/-, and UCP1-DTA mice compared with lean controls. Moreover, although resistin mRNA expression is upregulated by MTII treatment for 24 h and downregulated by CNTF(Ax15) treatment for 3 or 7 days, circulating resistin levels are not altered by MTII or CNTF(Ax15) treatment. In addition, serum resistin levels, but not resistin mRNA expression levels, are correlated with body weight, and neither resistin mRNA expression nor serum resistin levels are correlated with serum insulin or glucose levels. We conclude that transcriptional regulation of resistin in WAT does not correlate with circulating resistin levels and that circulating resistin is unlikely to play a major endocrine role in insulin resistance or glycemia in mice.
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MESH Headings
- Adipose Tissue/chemistry
- Adipose Tissue/drug effects
- Adipose Tissue/metabolism
- Animals
- Blood Glucose/drug effects
- Blood Glucose/physiology
- Body Weight/drug effects
- Carrier Proteins/genetics
- Ciliary Neurotrophic Factor/analogs & derivatives
- Ciliary Neurotrophic Factor/pharmacology
- Diet
- Diphtheria Toxin/genetics
- Disease Models, Animal
- Eating/drug effects
- Energy Intake/drug effects
- Gene Expression/genetics
- Hormones, Ectopic/blood
- Hormones, Ectopic/genetics
- Hormones, Ectopic/physiology
- Insulin/blood
- Insulin Resistance/physiology
- Ion Channels
- Male
- Membrane Proteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Obese
- Mice, Transgenic
- Mitochondrial Proteins
- Multivariate Analysis
- Obesity/chemically induced
- Obesity/metabolism
- Peptide Fragments/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Resistin
- Reverse Transcriptase Polymerase Chain Reaction
- Tumor Necrosis Factor-alpha/genetics
- Uncoupling Protein 1
- alpha-MSH/agonists
- alpha-MSH/analogs & derivatives
- alpha-MSH/pharmacology
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Otieno CJ, Bastiaansen J, Ramos AM, Rothschild MF. Mapping and association studies of diabetes related genes in the pig. Anim Genet 2005; 36:36-42. [PMID: 15670129 DOI: 10.1111/j.1365-2052.2004.01217.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mitogen-activated protein kinase 8 (MAPK8), resistin (RETN), 11 beta hydroxysteroid dehydrogenase isoform 1 (HSD11B1) and protein kinase B Akt2 (AKT2) genes are all genes known to affect insulin signalling and have been implicated in the progression of obesity and type 2 diabetes in humans. In this study, polymorphisms in the porcine diabetes related MAPK8, RETN, HSD11B1 and AKT2 genes were identified, mapped and their associations with phenotypic measurements in swine were analysed. Polymorphisms detected in the MAPK8, RETN and HSD11B1 loci were used to genotype a Berkshire-Yorkshire pig breed reference family. Using linkage analysis, RETN, HSD11B1 and MAPK8 genes were mapped to pig chromosomes 2, 9 and 14, respectively, while the AKT2 gene was physically mapped to pig chromosome 6q21. Results presented here suggest associations between the polymorphisms in the MAPK8, RETN and HSD11B1 genes with several phenotypic measurements, including fat deposition traits in the pig. Because these genes have been implicated in obesity and diabetes in humans, and this study suggests associations with fat related traits, further research on these genes in swine may provide useful information on genetic factors underlying lean pork production.
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Brown R, Wiesner G, Ur E, Wilkinson M. Pituitary resistin gene expression is upregulated in vitro and in vivo by dexamethasone but is unaffected by rosiglitazone. Neuroendocrinology 2005; 81:41-8. [PMID: 15809511 DOI: 10.1159/000084873] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Accepted: 01/13/2005] [Indexed: 12/30/2022]
Abstract
A physiological role for the adipose-derived hormone, resistin, remains unsolved and its putative involvement in insulin resistance is largely controversial. Like leptin and other adipokines, we detected resistin in the rodent hypothalamic-pituitary system. In addition, the pituitary corticotrope cell line, AtT20, is also a source of resistin. These data suggested that resistin could be involved in diverse physiological processes in non-adipose tissue. Initial studies indicated that pituitary resistin gene expression was regulated in a nutritional (fed>fasted), age- (young>old) and gender-specific manner (male>female). In the present work we hypothesized that pituitary resistin expression should be regulated through signalling pathways similar to those reported for adipose tissue. For example, dexamethasone (DEX) potently stimulates production of resistin in murine adipose tissue, whereas thiazolidinediones such as rosiglitazone (ROSI), acting via peroxisome proliferator-activated receptor (PPAR)gamma, reportedly inhibit or stimulate resistin expression. Using quantitative real-time RT-PCR we determined that injection of DEX (10 and 50 microg) yielded 7- and 9-fold increases in pituitary resistin gene expression in prepubertal, but not adult mice. In addition, adrenalectomy attenuated pituitary resistin gene expression, which was restored by DEX (10 microg). In AtT20 cells, exposure to corticosterone (10(-7) and 10(-6)M; 24 h) and DEX (10(-9)-10(-6)M) stimulated resistin mRNA more than 65% (p<0.05) and 115% (p<0.0001), respectively. In contrast, ROSI, injected (5 and 20 mg/kg s.c. for 14 days) or given orally (3 mg/kg/day to 10 mg/kg/day for up to 7 weeks), failed to alter pituitary resistin gene expression in healthy male CD1 mice. Treatment of AtT20 cells with ROSI (10(-5)-10(-10)M; 24 h or 96 h) or the PPARgamma agonist GW 1929 (10(-9) and 10(-5)M; 24 h) had no effect on resistin mRNA. The PPARgamma antagonist GW 9662 (10(-6) and 10(-5)M) was also ineffective. In conclusion, pituitary resistin mRNA levels are robustly stimulated by corticosteroids, particularly at the time of puberty. This is consistent with our previous suggestion that resistin may be involved in maturation of the hypothalamic-pituitary axis. In contrast, pituitary resistin gene expression appears to be PPARgamma-independent and therefore different from the situation in adipose tissue.
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Sato N, Kobayashi K, Inoguchi T, Sonoda N, Imamura M, Sekiguchi N, Nakashima N, Nawata H. Adenovirus-mediated high expression of resistin causes dyslipidemia in mice. Endocrinology 2005; 146:273-9. [PMID: 15471967 DOI: 10.1210/en.2004-0985] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The adipocyte-derived hormone resistin has been proposed as a possible link between obesity and insulin resistance in murine models. Many recent studies have reported physiological roles for resistin in glucose homeostasis, one of which is enhancement of glucose production from the liver by up-regulating gluconeogenic enzymes such as glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. However, its in vivo roles in lipid metabolism still remain to be clarified. In this study, we investigated the effects of resistin overexpression on insulin action and lipid metabolism in C57BL/6 mice using an adenoviral gene transfer technique. Elevated plasma resistin levels in mice treated with the resistin adenovirus (AdmRes) were confirmed by Western blotting analysis and RIAs. Fasting plasma glucose levels did not differ between AdmRes-treated mice and controls, but the basal insulin concentration was significantly elevated in AdmRes-treated mice. In AdmRes-treated mice, the glucose-lowering effect of insulin was impaired, as evaluated by insulin tolerance tests. Furthermore, total cholesterol and triglyceride concentrations were significantly higher, whereas the high-density lipoprotein cholesterol level was significantly lower. Lipoprotein analysis revealed that low-density lipoprotein was markedly increased in AdmRes-treated mice, compared with controls. In addition, in vivo Triton WR-1339 studies showed evidence of enhanced very low-density lipoprotein production in AdmRes-treated mice. The expressions of genes involved in lipoprotein metabolism, such as low-density lipoprotein receptor and apolipoprotein AI in the liver, were decreased. These results suggest that resistin overexpression induces dyslipidemia in mice, which is commonly seen in the insulin-resistant state, partially through enhanced secretion of lipoproteins.
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Xita N, Georgiou I, Tsatsoulis A, Kourtis A, Kukuvitis A, Panidis D. A polymorphism in the resistin gene promoter is associated with body mass index in women with polycystic ovary syndrome. Fertil Steril 2004; 82:1466-7. [PMID: 15533384 DOI: 10.1016/j.fertnstert.2004.04.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Revised: 04/12/2004] [Accepted: 04/12/2004] [Indexed: 11/19/2022]
Abstract
Resistin does not appear to be a major gene predisposing to polycystic ovary syndrome (PCOS). However, an association of a resistin variant with body mass index was found in women with PCOS, suggesting that resistin may be related to adiposity in PCOS.
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Huang SW, Seow KM, Ho LT, Chien Y, Chung DY, Chang CL, Lai YH, Hwang JL, Juan CC. Resistin mRNA levels are downregulated by estrogen in vivo and in vitro. FEBS Lett 2004; 579:449-54. [PMID: 15642357 DOI: 10.1016/j.febslet.2004.12.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2004] [Revised: 11/30/2004] [Accepted: 12/04/2004] [Indexed: 11/24/2022]
Abstract
Resistin, a hormone secreted by adipocytes, is suggested to be an important link between obesity and diabetes. The aim of this study was to evaluate the regulatory effect of estrogen on adipocyte resistin gene expression in ovariectomized (OVX) rats and in isolated rat adipocytes in vitro. Subcutaneous injection of estradiol benzoate reduced resistin mRNA levels in adipocytes isolated from the inguinal, parametrial, perirenal, retroperitoneal, or periovarian fat deposits of OVX rats, while an in vitro study showed that estradiol treatment decreased resistin mRNA levels in cultured rat periovarian fat adipocytes. Results of Western blotting analysis also showed that estrogen decreased adipose resistin contents in vivo and in vitro. These data suggest that estrogen is a pivotal negative regulator of resistin gene expression.
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