Leptin levels,leptin receptor gene polymorphisms,and energy metabolism in women

OBJECTIVE: Resting metabolic rate (RMR) is mainly determined by fat-free mass and additionally by age, sex, hormones, and possibly genetic differences. We evaluated whether leptin levels and polymorphisms in the leptin receptor (LEPR) gene were associated with energy expenditure phenotypes. METHODS: RMR, body composition, and leptin levels were measured in 125 overweight and obese women. Three LEPR polymorphisms, Lys109Arg, Gln223Arg, and Lys656Asn, were typed on genomic DNA of another group of 192 women in whom RMR was measured. Fat, protein, and carbohydrate oxidation were calculated for 103 of these subjects. In 38 subjects, glucose-induced thermogenesis was measured over 3 hours. RESULTS: In the first study group, a negative correlation between RMR and leptin levels was found after controlling for fat and fat-free mass. In multiple regression analysis, leptin contributed significantly to RMR, independent of body composition. In the second study group, RMR was not associated with LEPR polymorphisms. Differences in substrate oxidation rates were found among genotypes at the Lys656Asn site. In fasting conditions, Lys656Lys showed a trend to oxidize more carbohydrates and less fat than Asn656 carriers, a trend which became significant after the glucose load when carbohydrate oxidation rate in Lys656Lys was 15% higher than in Asn656 carriers (p = 0.04), and fat oxidation rate was 44% lower (p = 0.02). DISCUSSION: These results suggest that DNA sequence variations in the LEPR gene could affect substrate oxidation. We hypothesize that this might be caused by differences in glucose levels, leading to differences in glucose oxidation rates.     

Leptin responsiveness to energy restriction: genetic variation in the leptin receptor gene

Serum leptin concentrations are an important afferent signal in energy balance homeostasis. It has been speculated that the leptin responsiveness to energy restriction is affected by the functionality of the leptin receptor. The purpose of this analysis was to explore the effect of polymorphisms in the LEPR gene on the acute decline in leptin after 4 days of 65% energy restriction. Leptin concentrations of the study group (n = 44; all men) declined by 2.3 +/- 1.5 micro g/L [-39.4% (95% confidence interval: -43.6 to -34.9)]. Leptin responses did not statistically differ between noncarriers and carriers of three mutant variants of the polymorphisms: Lys109/Lys109 (-41.4%) vs. Arg109/+ (-37.0%) (p = 0.33); Gln223/Gln223 (-41.5%) vs. Arg223/+ (-37.8%) (p = 0.40); Lys656/Lys656 (-39.5%) vs. Asn656/+ (-39.3%) (p = 0.96). No effect of the assessed polymorphisms in the LEPR gene on the acute decline in leptin after energy restriction was observed. Power calculations are provided for future studies on the leptin responsiveness to energy restriction.     

瘦素受体Gln223Arg基因多态性与肥胖关系的研究

目的 研究瘦素受体Gln223Arg基因多态性与肥胖的关系。方法 2004年在山西省盂县选取一组人群，凋查其心血管病危险因素，同时抽血检测瘦素受体Gln223Arg基因多态性的基因型，并分析Gln223Arg基因多态性与肥胖的关系。结果 该组人群GG、GA及AA的基因型频率分别为0．7679、0．2171和0．0151；G和A等位基因频率分别为0．8764和0．1236。基因型频率分布符合Hardy-Weinberg平衡（P=0．934）。单因素分析结果表明携带A等位基因的研究对象具有更高的体重（63．2kg vs．61．9kg；P=0．0307）和体重指数（24．4kg／m^2 vs．24．1kg／m^2；P=00898）；在调整年龄、性别、体力活动和膳食之后，携带A等位基因者仍然具有较高的体重指数（24．5kg／m^2 vs．24．1kg/m^2；P=0．0396）和肥胖患病率（OR=1．30，95％CI：0．957～1．767；P=0．0935）。结论 瘦素受体Gln223Arg基因多态性与肥胖可能有关。     

中国人群瘦素受体Gln223Arg、Pr01019Pro基因多态性与肥胖关联性的Meta分析

目的 探讨瘦素受体(LEPR) Gln223Arg、Prol019Pro基因多态性与肥胖的关联性.方法 计算机检索万方、CNKI、维普、CBM、PubMed、EMBASE数据库,收集1979-2010年公开发表的关于中国人群LEPR Gln223Arg、LEPR Pro1 019Pro基因多态性与肥胖的病例对照研究的文献,选择OR值及其95％CI作为Meta分析指标.利用Stata 10.0软件对各研究结果进行异质性检验和效应值合并计算.结果 根据统一的纳入和剔除标准,纳入15篇文献,其中LEPRGln223Arg基因多态性相关文献9篇,共有肥胖者1096例,对照组949人;LEPR Prol019Pro基因多态性相关文献8篇,共有肥胖者961例,对照组818人.LEPR Gln223Arg基因多态性与肥胖关联性的研究中,LEPR-668位点基因G/A的OR=0.66(95％CI:0.49～0.89),将有A→3基因突变的AG基因型和GG基因型合并后与AA基因型比较,肥胖易感性降低(OR=0.50,95％CI:0.32～0.77)有统计学意义;在LEPR Prol019Pro基因多态性与肥胖关联性的研究中,LEPR-3057位点基因A/G的OR=1,61 (95％CI:1.15～2.26),有G→A基因突变的基因型AG和基因型AA合并后与GG基因型比较,肥胖易感性升高(OR=1.50,95％CI:1.08～2.08),有统计学意义.结论 中国汉族为主的人群LEPR Gln223Arg和LEPR Prol019Pro基因多态性与肥胖的发生均有关联.     

瘦素及瘦素受体基因多态性与乳腺癌的相关性研究

目的探讨瘦素及其瘦素受体基因多态性与乳腺癌发生的关系。方法采用PCR- RFLP对94例乳腺癌患者、128例健康对照者进行瘦素受体基因Gln223Arg多态性检测;ELISA分析法测定瘦素水平。结果乳腺癌组瘦素受体基因Gln223Arg的GG、GA和AA基因型表达频率分别为69.15%、17.02%和13.83%;等位基因G和A为77.66%和22.34%与对照组82.03%、15.63%和2.34%及等位基因的89.84%和10.16%相比较,差异有统计学意义(P=0.004,P=0.001)。乳腺癌组瘦素水平,腰臀比(WHR)明显高于对照组,差异均有统计学意义(P<0.01,P<0.001)。非条件logislic回归多因素分析表明,瘦素受体基因多态性、瘦素水平及WHR升高,与乳腺癌发生的相关危险度分别为:OR=4.87,95%CI:1.30-18.22,P=0.019;OR=1.53,95%CI:1.13-2.07,P= 0.006;OR=3.68,95%CI:1.34-10.11,P=0.011。结论瘦素受体基因Gln223Arg多态性、瘦素及WHR升高,可能增加乳腺癌发生的风险性。     

瘦素受体基因Gln223Arg多态性与肥胖的关联研究

目的探讨瘦素受体基因多态性与肥胖发生的关系。方法采用PCR-RFLP对502例肥胖患者、400例体重正常者进行瘦素受体基因Gln223Arg多态性检测。结果肥胖组瘦素受体基因Gln223Arg的GG、GA和AA基因型表达频率分别为0.777、0.197及0.026。单因素分析显示携带AA基因型与携带GG基因型相比,发生肥胖的风险为OR=0.478,P=0.043。多因素分析表明,瘦素受体基因多态性、年龄>65岁、吸烟以及口味偏重与肥胖发生的相对危险度分别为:OR=1.36,95%CI:0.999~1.849,P=0.05;OR=0.55,95%CI:0.366~0.825,P=0.004;OR=1.475,95%CI:1.064~2.045,P=0.02;OR=1.506,95%CI:1.042~2.176,P=0.029。结论瘦素受体基因Gln223Arg多态性可能与肥胖发生有关。     

Leptin, soluble leptin receptor, lipid profiles, and LEPR gene polymorphisms in Thai children and adolescents

OBJECTIVE: To evaluate the relationships between leptin, soluble leptin receptor, lipid profiles, and LEPR gene polymorphisms in child and adolescent Thai subjects. DESIGN: Cross-sectional study of Thai children and adolescents. SUBJECTS: 116 male and 65 female at risk for overweight/overweight child and adolescent Thai subjects, and 33 male and 62 female healthy child and adolescent Thai subjects (age: 5-19 years). MEASUREMENTS: Leptin levels, soluble leptin receptor levels, lipid profiles, LEPR gene polymorphisms. RESULTS: Significantly higher levels of cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), and leptin levels were observed in at risk for overweight/overweight group. On the other hand, high-density lipoprotein cholesterol (HDL-C) and soluble leptin receptor levels were significantly lower in the same group. Serum soluble leptin receptor levels were significantly negatively correlated with leptin. The at risk for overweight/overweight subjects with the Lys656Lys homozygous wild type LEPR gene had significantly higher cholesterol and LDL-C levels than those with Lys656Asn heterozygous and Asn656Asn homozygous mutant type. In contrast, subjects with Lys656Lys homozygous wild type had significantly lower leptin levels than those with Lys656Asn heterozygous and Asn656Asn homozygous mutant type. There was a statistically significant association between body mass index (BMI) and hyperleptinemia (odds ratio; OR = 2.49, p = 0.000) and females had more increased risk of hyperleptinemia than males (OR = 15.74, p = 0.004) in adolescent Thai subjects. CONCLUSION: The present study is the first report of Lys656Asn polymorphism of the LEPR gene associated with cholesterol, LDL-C, and leptin levels in Thai children and adolescents. Serum leptin levels were significantly higher in the at risk for overweight/overweight. In contrast, there were significantly lower soluble leptin receptor levels in the same group. In addition, there was a statistically significant association between BMI, sex, and hyperleptinemia in adolescent Thai subjects.     

LEPR基因Gln223Arg多态性与上海某区汉族儿童的相关性研究

目的探究瘦素受体基因Gln223Arg多态性与上海某区儿童超重肥胖的关系及相关生化指标的相关性。方法采用PCR-RFLP对上海松江区六所小学7-11岁超重肥胖与正常体重儿童(各262名)的血样进行LEPR基因Gln223Arg多态性检测,logistic回归分析其与儿童超重肥胖的相关性,并分析了生化指标在超重肥胖组与正常组儿童以及不同基因型间的差异。结果超重肥胖组与对照组之间LEPR基因Gln223Arg AA频率与A等位基因频率均无统计学差异(P>0.05)。对其收缩压(SBP),舒张压(DBP),胆固醇(TC),甘油三酯(TG),血糖(GLU),高密度脂蛋白胆固醇(HDL-C),低密度脂蛋白胆固醇(LDL-C)进行t检验,得出SBP,DBP,TG,HDL-C和LDL-C在超重肥胖组与对照组中差异显著。在控制了混杂因素BMI等后,LEPR基因Gln223Arg各基因型组的生化指标差异分析表明基因型可能与LDL-C相关(P<0.05)。进一步两两比较结果表明LDL-C水平在基因型AA组比AG(P=0.019)与GG组(P=0.017)低,而AG与GG组之间的差异无统计学意义(P=0.517)。结论 LEPR基因Gln223Arg多态性可能与儿童超重肥胖的发生无关,而LDL-C(P<0.05)可能与LEPR基因Gln223Arg基因型有相关性。     

青春期少女Leptin受体基因Gln223Arg多态性与体成分、骨密度关系的初步研究(英文)

目的初步探讨青春期少女Leptin受体基因Gln223Arg多态性与体成分、骨密度的关系。方法从北京地区随机抽取舞蹈专业15～17岁女生60名,以同年龄77名普通中学女生为对照。所有调查对象每天的膳食能量和营养素摄入情况用7天24小时膳食调查表收集。用"一年回顾身体活动调查表"了解其体力活动情况,此外测定所有调查对象的血清leptin、雌激素水平、骨矿含量、骨密度和体成分。用PCR-RFLP法分析其Leptin受体基因Gln223Arg的多态性。结果未见这些女生的Gln223Arg基因多态性与体成分间存在相关关系。携带Gln223等位基因的舞蹈专业女生的前臂骨密度明显低于不含该等位基因的个体(P<0.05);且携该基因型别的两组女生在所有检测部位的骨密度也均低于Arg223纯合子个体(P>0.05).结论Leptin受体基因Gln223Arg多态性可能是影响青春期少女骨密度及峰值骨量获得的一个遗传因素,但这种影响与BMI或体成分无关。此结果还有待进一步验证并揭示其内在机制。     

Genetics of leptin and obesity: a HuGE review

Leptin is an important regulator of the mass of adipose tissue and of body weight; it operates by inhibiting food intake and stimulating energy expenditure. Some polymorphic genes involved in the regulation of leptin-the leptin gene (LEP A19G), the leptin receptor gene (LEPR Q223R, K109R, and K656N), and the peroxisome proliferator-activated receptor-gamma gene (PPARG P12A and C161T)--have been investigated as possible factors associated with obesity. Allelic frequencies of these polymorphisms show ethnic variation. The authors performed a meta-analysis of the available data on the association between these polymorphisms and obesity based on case-control studies. Odds ratios and 95% confidence intervals for obesity associated with leptin polymorphisms were calculated by using both fixed- and random-effects models. Results suggest no evidence of association between the genes under study and obesity. The lack of association could be due to the complex pathogenesis of obesity, which involves a number of genetic and environmental factors. Large studies including testing of multiple genes in both obese and lean subjects, with epidemiologic data on dietary habits in different ethnic groups, are necessary to better understand the role of leptin in regulating weight in human populations.     

No association of defined variability in leptin,leptin receptor,adiponectin, proopiomelanocortin and ghrelin gene with food preferences in the Czech population

Abstract

Background: Previously, it has been reported that mutations in the genes encoding for adipokines may be associated with impaired food intake and may serve as potential obesity biomarkers. The aim of this study was to investigate the possible associations of defined variability in leptin, leptin receptor, adiponectin, proopiomelanocortin and ghrelin genes with food preferences in the obese and non-obese Czech population and evaluate their potential as the obesity susceptibility genes.

Patients and Methods: Using PCR followed by restriction analysis, we studied 185 volunteers. Basic anthropometrical characteristics associated to obesity were measured and the food intake was monitored using a 7-day record method. In the group of obese individuals, a subset of 34 morbidly obese patients was studied for plasma leptin and soluble leptin receptor levels.

Results: None of the examined polymorphisms was associated to anthropometrical or demographic characteristics of the study subjects. The Gln223Arg polymorphism within the leptin receptor gene was significantly associated with lower plasma leptin levels (the RR genotype being more frequent in patients with lower plasma leptin levels; P = 0.001). No associations of the examined polymorphisms with food preferences was observed.

Conclusions: Based on our results, the examined polymorphisms in the adipokine genes do not seem to be the major risk factor for obesity development in the Czech population nor significantly affect food preferences.     

LEPR G1n223Arg多态性对不同种族人群中乳腺癌危险性影响的meta分析

瘦素和瘦素受体参与了乳腺癌的发生发展过程。在瘦素受体基因（LEPR）6号外显子上第223个密码子A到G的转变可以导致谷氨酸到精氨酸的替换（Gln223Arg）。许多已发表的病例对照研究评价了LEPRGln223Arg多态性与乳腺癌的关系。然而,却未得出一致的结论。本篇meta分析囊括了8篇文献来评价LEPRGln223Arg多态性与乳腺癌的联系。用总体合并OR值作为研究共显性模型、隐性模型、显性模型的指标。结果显示总体研究中隐性模型（OR=1．32,95％CI：1．03～1．69）和Arg/Gln vs Gin／Gin基因型（OR=1．16,95％CI：1．01～1．34）显著提高了乳腺癌的危险性。种族分层分析中发现,非洲人群的以下几个基因型会提高患乳腺癌的危险性：Arg/Arg vs 8Gln/Gln（OR=1．86,95％CI：1．28-2．71）,Arg／Gln vs GIn/Gln（OR=1．48,95％CI：1．10—1．99）,显性模型（OR=1．60,95％CI：1．21～2．11）和隐性模型（OR=1．48,95％cI：1．07～2．05）;亚洲人群中,Arg／ArgvsGin／Gin基因型（OR=6．79,95％CI：3．42～13．47）和显性模型（OR=2．03,95％CI：1．42～2．90）提高了患乳腺癌的危险性。在欧洲人群中任何基因模型都没有发现能显著提高乳腺癌的危险性。总而言之,LEPR223Arg是乳腺癌发展的低风险因素,特别是在非洲女性中。     

Association of Gln223 Arg polymorphism of the leptin receptor gene with indicators of energy expenditure in obese children

ObjectiveGln223 Arg polymorphism of the leptin receptor (LEPR) gene is one of the most frequently examined polymorphisms of this gene and has been suggested to be associated with energy expenditure (EE). The aim of the present study was to investigate the association of this variant on indicators of EE—resting metabolic rate (RMR), postabsorptive and postprandial respiratory quotient (RQ), and food-induced thermogenesis (FIT)—in obese children.MethodsThe study included 486 genotyped children (obese, n = 355). RMR was measured by indirect calorimetry for 45 min. Subsequent to test-food consumption, FIT was measured in a subsample of obese children (n = 121, body mass index 31.9 kg/m² (mean ± SD 5.1).ResultsObese children with the Gln223 Gln genotype showed a significantly lower post-absorptive and postprandial RQ (P = 0.0055 versus P = 0.0002, adjusted for age, sex, and lean body mass) than did groups of children with Gln223 Arg and Arg223 Arg genotypes. No significant differences were observed in FIT and RMR among the carriers and non-carriers of the 223 Arg allele.ConclusionThe significantly lower post-absorptive and postprandial RQ in the group of Gln223 Gln genotype children indicates that the fat oxidation of these children maybe increased before and subsequent to food consumption, which can be important in the planning of diet of these children.     

Nutritional treatment for acquired immunodeficiency virus-associated wasting using beta-hydroxy beta-methylbutyrate, glutamine, and arginine: a randomized, double-blind, placebo-controlled study

BACKGROUND: The current study was designed to examine whether a combination of three nutrients, consisting of beta-hydroxy-beta-methylbutyrate (HMB), a metabolite of leucine, L-glutamine (Gln) and L-arginine (Arg), each of which has been previously shown to slow muscle proteolysis, could synergistically alter the course of muscle wasting in patients with established acquired immunodeficiency syndrome (AIDS). METHODS: Sixty-eight human immunodeficiency virus (HIV)-infected patients with a documented weight loss of at least 5% in the previous 3 months were recruited from the HIV clinic at Nassau County Medical Center. The subjects were randomly assigned in a double-blind fashion to receive either placebo containing maltodextrin or the nutrient mixture (HMB/Arg/Gln) containing 3 g HMB, 14 g L-glutamine, and 14 g L-arginine given in two divided doses daily for 8 weeks. Body weights (BW) were recorded weekly and lean body mass (LBM) and fat mass (FM) were measured by air displacement plethysmography and by a single computerized tomography (CT) slice through the thigh at 0, 4, and 8 weeks. RESULTS: Forty-three subjects completed the 8-week protocol, (placebo, n = 21; HMB/Arg/Gln, n = 22). At 8 weeks, the subjects consuming the HMB/Arg/Gln mixture gained 3.0 +/- 0.5 kg of BW while those supplemented with the placebo gained 0.37 +/- 0.84 kg (p = .009). The BW gain in the HMB/Arg/Gln-treated subjects was predominantly LBM (2.55 +/- 0.75 kg) compared with the placebo-supplemented subjects who lost lean mass (-0.70 +/- 0.69 kg, p = .003). No significant change in FM gain was observed (0.43 +/- 0.83 kg for the group receiving HMB/Arg/Gln and 1.07 +/- 0.64 kg for the group receiving the placebo, p > .20). Similar percentage changes in muscle mass and fat mass were observed with CT scans. Immune status was also improved as evident by an increase in CD3 and CD8 cells and a decrease in the HIV viral load with HMB/Arg/Gln supplementation. CONCLUSIONS: The data indicate that the HMB/Arg/Gln mixture can markedly alter the course of lean tissue loss in patients with AIDS-associated wasting.     

Effect of genetic variation in the leptin gene promoter and the leptin receptor gene on obesity risk in a population-based case-control study in Spain

There are no good genetic markers for incorporating the study of genetic susceptibility to obesity in epidemiological studies. In animal models, the leptin (LEP) and the leptin receptor (LEPR) genes have been shown to be very important in obesity because leptin functions as a negative feedback signal in regulating body-weight through reducing food intake and stimulating energy expenditure. In humans, several polymorphisms in these genes have been described. However, their association with obesity is still very controversial because there are no good case-control studies designed to specifically test this association. Our objective has been to conduct a population-based case-control study to estimate the risk of obesity arising from the −2548G > A and Q223R polymorphisms in the LEP and LEPR genes, respectively. 303 obese cases (101 men and 202 women) and 606 controls (202 men and 404 women) were selected from a Spanish Mediterranean population. Genetic, clinical and life-style characteristics were analyzed. No association was found between the −2548G > A polymorphism and obesity. However, the Q223R variant was significantly associated with obesity in a recessive model, the RR genotype being more prevalent in controls than in obese subjects. The inverse association between the Q223R polymorphism and obesity (OR = 0.62; 95% CI: 0.39–0.99) remained significant even after additional adjustment for education, tobacco smoking, alcohol, physical activity, origin of the obese patient, and the −2548G > A polymorphism in the LEP gene (OR = 0.54; 95% CI: 0.32–0.89). In conclusion, the −2548G > A polymorphism is not a relevant obesity marker in this Mediterranean population, although Q223R does seen to be so.     

Improvement of metabolism among obese breast cancer survivors in differing weight loss regimens

OBJECTIVE: To compare the efficacy of different weight loss regimens on body weight loss and metabolic improvement in breast cancer survivors. RESEARCH METHODS AND PROCEDURES: Forty-eight obese breast cancer survivors were randomly divided into four groups and were followed for 1 year: 1) the Control group (subjects did not receive specific nutrition counseling); 2) the Weight Watchers group (subjects were given free coupons to attend weekly Weight Watchers meetings); 3) the Individualized group (a registered dietitian provided one-on-one nutritional counseling); and 4) the Comprehensive group (subjects received individualized dietary counseling and free coupons for the weekly Weight Watchers meetings). At baseline and 3-, 6-, and 12-month data collection visits, a fasting blood sample was obtained for assays. A three-day dietary record was kept during the week before these visits and dietary intake was analyzed. RESULTS: Subjects in the three intervention groups lost weight (Control: 1.1 +/- 1.7 kg; Weight Watchers: -2.7 +/- 2.1 kg; Individualized: -8.0 +/- 1.9 kg; Comprehensive: -9.5 +/- 2.7 kg) and percentage body fat, but only the Individualized and Comprehensive groups had significant losses. Subjects in the Comprehensive group showed the most improvement in cholesterol levels and had reductions in blood leptin levels. DISCUSSION: Because insulin resistance and high blood leptin levels are associated with breast cancer, losing weight to improve these parameters may reduce the risk of recurrence. Only subjects in the Comprehensive group showed significant reductions in body weight and fat, energy intake, and leptin levels. For breast cancer survivors, different weight loss strategies should be considered to assist them in losing weight.     

瘦素受体基因多态性与2型糖尿病合并非酒精性脂肪肝的关系

目的探讨瘦素受体（LEPR）基因G3057A多态性与2型糖尿病合并非酒精性脂肪肝的关系。方法以216例新诊断的2型糖尿病患者（包括104例合并非酒精性脂肪肝）及108例正常糖耐量者作为受试对象，采用半巢式PCR-RFLP和PCR产物直接测序法检测各组的基因变异频率，ELISA法检测各组瘦素及胰岛素水平，常规检测血糖、血脂等代谢参数。结果2型糖尿病合并非酒精性脂肪肝组具有较高的谷丙转氨酶、甘油三酯、低密度脂蛋白胆固醇、瘦素水平和较低的胰岛素水平。其3057位核苷酸G—A变异频率为76．0％，也明显高于2型糖尿病不伴脂肪肝组及糖耐量正常组（分别为62．1．3％，53．2％），差异有统计学意义（X^2=14．63，P〈0．01）。结论LEPR第3057位核苷酸基因多态性可能通过调节机体脂质代谢、影响机体胰岛素敏感性等途径参与2型糖尿病合并非酒精性的发生。     

瘦素受体基因多态性与壮族儿童单纯性肥胖的相关性研究

目的 探讨瘦素受体(leptin receptor,LEPR)基因单核苷酸多态性位点rs1137100 与壮族儿童单纯性肥胖的相关性。方法 对208名柳州某区小学学龄前儿童(年龄均<7岁)分别检测身高和体重,计算BMI。利用SNaPshot技术分析107例单纯性肥胖儿童和101例健康对照儿童的LEPR 基因型及等位基因频率分布状况。结果 肥胖和健康对照组LEPR 基因A/A型、A/G型及G/G型基因型频率分别为66.4%、29.9%、3.7%和68.3%、27.7%、4.0%,两组等位基因频率分别为81.3%、18.7%和82.2%、17.8%,A等位基因的OR值为1.06,95%CI为0.64~1.74。两组基因型与等位基因频率差异均无统计学意义(P>0.05);肥胖与健康对照组LEPR 基因型频率在性别分层中差异均无统计学意义(P>0.05)。肥胖组的BMI水平明显高于对照组,差异有统计学意义(P<0.05)。而肥胖组中各基因型间BMI水平的差异无统计学意义(P>0.05)。经Hardy-Weinberg遗传平衡定律检验,其等位基因在两种人群中的分布符合遗传平衡,说明样本具有群体代表性。而该位点的等位基因及基因型频率在所收集的肥胖组与对照组样本中分布未见显著异常。结论 LEPR基因rs1137100位点多态性与广西壮族学龄前儿童单纯性肥胖无相关性。     

Leptin and leptin-receptor polymorphisms in fertile and infertile men

The association of leptin (LEP) -2548G/A and/or leptin receptor (LEPR) Gln223Arg polymorphisms with male infertility and plasma FSH, LH, and testosterone (T) levels was examined. The genotypes and allele frequency distributions of LEP -2548G/A and LEPR Gln223Arg polymorphisms were investigated in 150 fertile and 150 infertile men by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Also, plasma levels of FSH, LH, and T were measured using commercial ELISA kits. Frequencies of AA, AG and GG genotypes of LEP-2548G/A polymorphism were statistically different in fertile and infertile men (p=0.012). The AG genotype showed a protective effect which could decrease risk of male infertility about 3 fold (p = 0.004). We did not observe any differences in frequencies of LEPR Gln223Arg alleles and genotypes between groups (p > 0.05). Sperm counts from infertile men with the AG and GG genotypes of the LEP polymorphism were significantly higher than AA genotype (p<0.05). Moreover, infertile men who carried the RR genotype of LEPR showed a statistically higher percentage of sperm with progressive motility than individuals with other genotypes (p = 0.004). There was no correlation between different combinations of LEP and LEPR genotypes and LH, FSH, and T levels (p > 0.05). Our study suggests that the LEP -2548G/A polymorphism may play a role in male fertility and the AG genotype may have a protective effect through increasing sperm counts. The distribution of genotypes of LEP -2548G/A polymorphism are different in fertile and infertile males and may be a useful tool in evaluation of male infertility.

Abbreviations: LEP: leptin; LEPR: leptin receptor; T: testosterone; FSH: follicle-stimulating hormone; LH: luteinizing hormone     

Serum leptin and weight gain over 8 years in African American and Caucasian young adults

OBJECTIVE: There is considerable interest in how to prevent weight gain in adulthood. Leptin, a peptide hormone expressed in adipose tissue, is believed to signal the central nervous system about the level of body fat stores, and thereby may control appetite. Little information exists on whether the serum leptin concentration influences long-term weight changes in the free-living population. RESEARCH METHODS AND PROCEDURES: From an ongoing cohort study of young African American and white adults, we selected a sample of participants (n=492), stratified on sex, race, and weight changes over 8 years. Serum leptin was measured on stored specimens using a radioimmunoassay. Weight change was modeled in relation to baseline leptin concentrations. RESULTS: Cross-sectionally, leptin concentration was associated positively with body mass index, negatively with physical activity level, and was higher in women than men. These variables explained 72% of the variance in serum leptin. Over the 8 years, the sample gained an average of 7.8 kg (standard deviation = 10.8). There was no evidence that 8-year weight change was associated with initial leptin concentration: 8-year weight change was only 0.5 kg less (95% confidence interval =-1.8 to 0.8, p = 0.47) per each 10 ng/ mL increment (approximately one standard deviation) of baseline leptin. In contrast, leptin change correlated highly (r=0.62) with weight change. DISCUSSION: Our data corroborate evidence that adiposity determines leptin levels but do not support the hypothesis that leptin deficiency plays an important role in obesity in the general population.