多囊卵巢综合征高雄激素血症患者瘦素水平的检测及评价

目的探讨多囊卵巢综合征高雄激素血症进行患者瘦素(Leptin)水平及其与睾酮(T)、体重指数(BMI)的关系.方法采用放射免疫分析法(RIA)检测53例PCOS患者血清瘦素水平,其中非肥胖组PCOS患者36例,正常对照30例;肥胖组PCOS患者17例,正常对照20例.结果肥胖组及非肥胖组PCOS高雄激素血症患者血清瘦素水平均明显高于相当体重指数的正常对照组,有显著差异(p均＜0.01);两组瘦素水平分别与其睾酮水平进行相关性分析,均显著正相关(r=0.51,p＜0.01和r=0.58,p＜0.01);非肥胖组PCOS患者血清瘦素水平与其BMI相关分析显示,无相关性;肥胖组PCOS患者血清瘦素水平与其BMI进行相关分析,显著正相关(p=0.56,p＜0.01).结论高瘦素血症是PCOS患者的内分泌特征之一,PCOS高雄激素血症的形成与高瘦素水平有关;超重或肥胖的PCOS高雄激素血症患者存在瘦素抵抗现象.     

The relationship between plasma leptin and nutritional status in chronic hemodialysis patients

Leptin serves an important role in suppressing appetite in mice and is known to be elevated in chronic renal failure (CRF) patients. But clinical significance of leptin as an appetite-reducing uremic toxin, remains to be determined. So we studied the relationship between plasma leptin and nutritional status in 46 chronic hemodialysis (HD) patients. Pre HD leptin was measured and divided by body mass index (BMI) to give adjusted leptin levels. KT/Vurea (K, dialyzer urea clearance; T, duration of HD; V, volume of distribution of urea), C-reactive protein (CRP), plasma insulin and nutritional parameters such as serum albumin, normalized protein catabolic rate (nPCR), subjective global assessment (SGA), BMI and mid-arm muscle circumference (MAMC) were also measured. Mean plasma leptin levels were 8.13+/-2.91 ng/mL (male 3.15+/-0.70; female 14.07+/-6.14, p<0.05). Adjusted leptin levels were positively correlated with nPCR (male r=0.47, p<0.05; female r=0.46, p<0.05), SGA (male r=0.43, p<0.05; female r=0.51, p<0.05) and MAMC (male r=0.60, p<0.005; female r=0.61, p<0.05). They did not correlate with KT/Vurea, serum albumin, hematocrit, bicarbonate, insulin and CRP. Presence of DM and erythropoietin therapy had no effect on leptin levels. These results suggest that leptin is a marker of good nutritional status rather than a cause of protein energy malnutrition in chronic HD patients.     

血瘦素遗传度的双生子分析

目的　观察遗传因素对血瘦素的影响。方法　 5 7对双生子 ,用微卫星 DNA基因扫描和分型技术 ,根据基因型的一致性来鉴别卵性。双生子间异同比较估计遗传和环境的相对效应 ,用放免法测定血清瘦素。结果　异卵双生子 (dizygotic,DZ)瘦素的对内方差大于同卵双生子 (monozygotic,MZ)的对内方差 (P<0 .0 5 ) ,前者为后者的 2倍多。但当校正体重指数 (body mass index,BMI)、性别和血尿酸 (uricacid,UA)后 ,MZ的对内方差接近于 DZ的对内方差。血瘦素的遗传度 8% ,校正 BMI、性别等的影响后血瘦素的遗传度为 0 .18%。血压与瘦素在简单相关分析时相关 (收缩压 r=0 .35 5 ,P<0 .0 0 1;舒张压 r=0 .339,P<0 .0 0 1) ,多元逐步回归分析时仅 BMI、性别和 UA入选方程 (R2 =0 .788,P<0 .0 0 1)。结论　遗传因素对血瘦素影响不大 ,血瘦素主要受环境因素影响。     

Antiestrogenic tamoxifen and toremifene increase serum leptin levels in postmenopausal breast cancer patients

OBJECTIVES: Because estrogens stimulate the synthesis and release of leptin in the adipocytes, the effect of antiestrogens on the circulating leptin levels were studied. METHODS: Thirty postmenopausal patients with breast cancer were randomized to start either with tamoxifen (20 mg/day, n=15) or toremifene (40 mg/day, n=15), and the patients were examined and serum leptin concentrations measured before the study and at 6 and 12 months. RESULTS: The baseline leptin concentrations ranged from 4.4 to 60.0 microg/l (15.3+/-13.1 microg/l, mean+/-S.D.), and it correlated positively with the body mass index (BMI) of the subjects (r=0.73, P=0.0001). Taking as a whole the antiestrogen regimen was associated with elevated leptin levels at 6 months (19.5+/-13.8 microg/l, P=0.0001) but no excess increase in leptin levels were seen at 12 months (20.9+/-13.5 microg/l, NS). Subgroup analysis showed no difference between the effects of tamoxifen or toremifene on leptin. BMI increased in 21 women (from 26.2+/-4.3 to 27.3+/-4.8 kg/m2, P=0.0001) at 6 months, but not after that; in nine women BMI did not change. There was no significant correlation between the change in leptin levels and the change in BMI in either group implying that antiestrogens may specifically stimulate leptin production. CONCLUSIONS: Antiestrogens may stimulate the synthesis and release of leptin in the adipocytes. This effect of antiestrogens resembles the effect of estrogen and consequently stimulation of leptin production can be added to the estrogenic effects of antiestrogens.     

肥胖患者血清瘦素、C-肽和外周脂肪组织中瘦素受体水平的变化分析

目的 :通过对肥胖及伴有 2型糖尿病患者瘦素、C -肽及外周脂肪组织leptin受体表达的研究 ,进一步探讨肥胖及肥胖伴 2型糖尿病患者发生发展的机制。方法 :用放射免疫分析和放射配基结合实验的方法 ,对 91例受检者 (其中肥胖 38例 ,超重 2 3例 ,正常对照 30例 )外周脂肪组织leptin受体的密度及血清中的瘦素、C -肽水平进行检测。结果 :随着BMI的增加 ,瘦素受体密度肥胖组和超重组与正常组比较差异十分显著(p <0 0 1) ,肥胖组与超重组比较有显著性差异 (p <0 0 1) ;而受体与瘦素结合的能力 (Kd值 )没有显著性差异(p >0 0 5 )。三组间的Kd值无差异。从散点分布图可以看出体重指数越大其leptin受体的密度就越小 ,BMI与Bmax相关性 (r=- 0 70 ,p<0 0 1) ;在超重和肥胖伴有 2型糖尿病患者 ,血清中的瘦素和C -肽水平肥胖组比超重组明显升高 ,二者的比值有明显差异 (p <0 0 1) ;血清C -肽增高幅度比瘦素明显 ;血清C -肽水平与体重指数呈正相关。结论 :单纯性肥胖及肥胖伴 2型糖尿病患者血清瘦素、C -肽水平及外周脂肪组织中leptin受体的密度的变化与BMI密切相关 ,肥胖病人所并发的 2型糖尿病与瘦素抵抗和胰岛素抵抗密切相关     

Proopiomelanocortin gene variants are associated with serum leptin and body fat in a normal female population

A major quantitative trait locus (QTL) determining leptin levels has been linked to the proopiomelanocortin (POMC) region on chromosome 2. Most studies, based on under 350 lean or obese subjects, have shown no association between POMC SNP 8246 C/T and serum leptin, but significant associations have been reported with RsaI 8246 C/T SNP haplotypes. We have investigated association of four POMC SNPs with body composition and serum leptin in 2758 normal Caucasian female subjects (mean age 47.4+/-12.5 years), from the St Thomas' UK Adult Twin Registry (Twins UK): RsaI and 51 G/C in the 5'UTR and 8246 C/T and 7965 C/T in the 3'UTR. Under the recessive model, the 8246 T allele (freq. 0.18) was significantly associated with higher mean BMI (P=0.032) and total fat (P=0.046, both after age adjustment). Significant associations were maintained in sib-TDT with waist (P=0.049), total fat (P=0.037) and emerged with serum leptin (P=0.016). Initial significant associations between RsaI (-) allele (freq. 0.30) and higher waist (P=0.04) or % central fat (P=0.02) were not maintained in sib-TDT. No significant associations were found between body composition or serum leptin and RsaI/8246 C/T haplotype and none with 51 G/C (freq. 0.01) or 7965 C/T (freq. 0.004). There was minimal pairwise LD between the four loci, apart from RsaI and 8246 C/T (D'=-0.78 (P<0.0001)). Associations of BMI, weight and total fat with SNPs in regions flanking the POMC gene in this powerful study suggest that regulation of POMC expression may be influential in determining body weight.     

原发性高血压患者颈动脉斑块及动脉僵硬度与血清尿酸水平的关系*

 目的：研究原发性高血压（essential hypertension,EH）患者颈动脉斑块性质及动脉僵硬度与血清尿酸（uric acid,UA）水平的关系。方法：选择EH患者92例,健康对照组30例;对所有研究对象行相关血液生化检查,检测颈总动脉内中膜厚度（IMT）、颈动脉斑块和颈股动脉脉搏波传导速度（CFPWV）。结果：EH组的血清UA明显高于对照组［（361.51±83.81)μmol/L vs (317.03±62.22) μmol/L,P<0.05］;EH组IMT及异常检出率较对照组明显升高［(0.69±0.14) mm vs (0.60±0.12) mm,42.39% vs 10.00%,P<0.05］;45例EH患者检出颈动脉斑块,随着颈动脉斑块严重程度增高,血清UA水平依次增高［（285.25±78.41) μmol/L、(341.19±63.99) μmol/L和(401.33±88.49) μmol/L,P<0.05］;软斑块组（n=11）的血清UA水平较硬斑块组（n=34）显著增高［（389.00±69.45) μmol/L vs (323.03±72.71) μmol/L,P<0.05］。多元线性逐步回归分析显示CFPWV与年龄（r=0.414）、收缩压（r=0.224）、脉压（r=0.270）和血清UA（r=0.219）呈显著正相关（P<0.05）。结论：血清UA水平增高是EH发病的危险因素之一,血清UA水平可反映颈动脉斑块的严重程度及稳定性,EH患者随着血清UA水平增高大动脉弹性减退。     

瘦素和脂联素在儿童肥胖相关性高血压发病中的作用

目的探讨瘦素和脂联素在儿童肥胖相关性高血压发病中的作用。方法基于北京市儿童青少年代谢综合征研究项目的现况调查结果,非随机选择3502名6-18岁学龄儿童（其中男1784名,女1718名）为研究对象,按照超重（包括肥胖）和高血压状态将研究对象分为4组,正常体重正常血压组（对照组,1497名）、正常体重高血压组（HBP组,125名）、超重但血压正常组（OB组,1349名）和超重合并高血压组（OB＋HBP组,531名）。通过比较4组人群血清瘦素和脂联素水平,以及瘦素和脂联素与血压之间的相关回归分析,探讨其与肥胖和血压之间的关系。结果超重肥胖人群BMI、血压、胰岛素和瘦素水平显著升高,脂联素水平降低。HBP组与对照组BMI、瘦素、脂联素水平差异无统计学意义。OB组和OB＋HBP组与对照组比较,BMI、SBP、DBP、胰岛素和瘦素水平升高,脂联素水平降低,与HBP组比较仍可见BMI、胰岛素和瘦素水平升高,脂联素水平降低。与OB组比较,OB＋HBP组BMI和胰岛素水平及男性的瘦素水平明显升高。血压与年龄、BMI、胰岛素、瘦素均呈显著正相关（r=0.260-0.643,P〈0.01）,与脂联素呈显著负相关（r=-0.171--0.332,P〈0.01）。但在调整胰岛素或BMI后,瘦素、脂联素与血压的相关性减弱或消失。结论超重人群血压、胰岛素及瘦素水平均高于对照人群,脂联素水平低于对照人群。瘦素、脂联素可能通过肥胖或胰岛素抵抗与血压相关。     

Relationships between the serum levels of soluble leptin receptor and free and bound leptin in non-pregnant women of reproductive age and women undergoing controlled ovarian hyperstimulation

BACKGROUND: The aim of this study was to investigate the relationships between the serum levels of soluble leptin receptor (SLEPR), and total, free and bound leptin, and the change in the serum SLEPR level during an IVF cycle. METHODS: Serum concentrations of leptin and SLEPR were measured in 50 Japanese women of reproductive age, and 20 patients participating in an IVF programme. The total leptin was fractionated into free and bound portions by gel filtration chromatography. RESULTS: The SLEPR level was negatively correlated with the body mass index (BMI) (r = -0.548, P < 0.0001), total leptin (r = -0.433, P < 0.0001), the percentage of free leptin (r = -0.732, P < 0.0001) and the absolute free leptin concentration (r = -0.506, P < 0.0001). The SLEPR level was positively correlated with the percentage of bound leptin (r = 0.730, P < 0.0001), whereas there was little variation in the absolute bound leptin concentration, regardless of the BMI or SLEPR concentration. During the IVF cycle, total and free leptin elevated during maximal ovarian stimulation, whereas there was no significant difference in the SLEPR concentration. CONCLUSIONS: The results demonstrate a skillful mechanism where a change in the serum SLEPR level regulates, in part, the biological activity of leptin in the circulation.     

非酒精性脂肪性肝病与血尿酸水平测定及其临床意义

目的 探讨非酒精性脂肪性肝病（NAFLD）与血尿酸水平的关系。方法 选取在我院常规体检的2666例成人,其中经腹部彩超诊断为脂肪肝者为NAFLD组共603例,无脂肪肝者为非NAFLD组共2063例。根据BMI将其分为肥胖组290例及非肥胖组2376例。回顾性分析研究对象的年龄、血压、UA、FBG、TC、TG、LDL、GDL等临床指标。结果 NAFLD组的年龄、收缩压、舒张压、UA、FBG、TC、TG、LDL均高于非NAFLD组,差异具有统计学意义（P＜0.05）;而NAFLD组的HDL水平低于非NAFLD组,差异具有统计学意义（P＜0.05）。肥胖组的年龄、收缩压、舒张压、UA、FBG、TC、TG、LDL均高于非肥胖组,差异具有统计学意义（P＜0.05）;而肥胖组的HDL水平低于非肥胖组,差异具有统计学意义（P＜0.05）。在肥胖组中,血尿酸水平与是否发生NAFLD无明显相关关系（r=0.095,P=0.107）,而在非肥胖组中,血尿酸水平与是否发生NAFLD呈正相关关系（r=0.229,P=0.000）。结论 在非肥胖人群中,高尿酸血症可作为NAFLD的独立危险因素,为临床上NAFLD的治疗提供一定的实用价值。     

二甲双胍对奥氮平致体重增加的精神分裂症患者血清瘦素水平的影响

目的观察并分析二甲双胍对奥氮平治疗后体重增加的精神分裂症患者血清瘦素的影响。方法单一接受奥氮平治疗并出现有临床意义体重显著增加(≥7%)的精神分裂症患者,随机分组后分别加用(二甲双胍组,n=35)或不加用(对照组,n=35)二甲双胍(750mg/d)辅助治疗,于治疗前及治疗后4、8周末分别测定体质量指数(BMI)、血清瘦素、稳态模型评估的胰岛素抵抗指数(HOMA-IR)。结果①二甲双胍组治疗后4、8周时,瘦素、HOMA-IR均较治疗前显著下降(P0.05~0.01);治疗8周时BMI较治疗前显著下降(P0.05)。对照组治疗4、8周时,BMI、瘦素、HOMA-IR与治疗前比较无显著差异;②两组治疗前及治疗后4、8周时,血清瘦素水平与BMI、HOMA-IR均有显著相关(r=0.356~0.463,P=0.036~0.004);二甲双胍组治疗后4、8周时,血清瘦素治疗前后的变化值与BMI、HOMA-IR治疗前后的变化值均有显著相关(r=0.341~0.404,P=0.042~0.015)。结论二甲双胍辅助治疗可显著降低奥氮平所致体重增加的精神分裂症患者血清瘦素水平,并与其对体重、胰岛素抵抗的改善有关。     

Interrelationships of serum estradiol, estrone, and estrone sulfate, adiposity, biochemical bone markers, and leptin in post-menopausal women

OBJECTIVE: The aim of this study was to examine the relationships between endogenous estrogens and adiposity, bone markers, and leptin in post-menopausal (PM) women. DESIGN: Seventy-three post-menopausal (PM) women participated in a clinical correlational study. Weight, height, waist-hip ratio, fasted morning serum and first morning voided urine samples were obtained to compare body mass index (BMI), waist-hip ratio, endogenous estrogens, leptin, and bone markers. Serum estradiol, estrone (E1), estrone sulfate (E1S), leptin, osteocalcin, and urinary deoxypyridinoline (Dpd) were determined. RESULTS: Significant positive relationships were found between BMI and estradiol, E1, and E1S (r = 0.52, 0.38, and 0.29; P < or = 0.001, 0.001, and 0.013 respectively). Significant relationships between leptin and estrogens were revealed, but were not significant when BMI was used as a covariate. Although many subjects revealed elevated bone marker levels, no correlation between estrogens or BMI and bone markers (Dpd and osteocalcin) was found. CONCLUSIONS: There are significant positive correlations between estrogens and BMI in PM women. Increasing levels of estradiol, E1, and E1S with increasing BMI may be an indicator of adiposity, but are without effect as a stimulatory factor on leptin production. Waist-hip ratio did not significantly affect leptin concentrations when accounting for BMI. Due to assay sensitivity in the present study, data represent a more precise representation of these relationships. The lack of correlation between estrogens and bone marker levels may have been due to low estrogen levels in PM women.     

The influence of hormone replacement therapy (HRT) on serum leptin concentration in postmenopausal women

OBJECTIVE: This study aimed to evaluate the influence of hormone replacement therapy (HRT), the estradiol concentration and body mass index (BMI, kg/m(2)) on the serum leptin concentration in postmenopausal women. SUBJECTS AND METHODS: 352 healthy postmenopausal women (mean age, 60.9 +/- 8.5 years) participated in this comparative study. 71 (30%) women (mean age 55.9 +/- 8.3 years) had taken HRT, while 281 (70%) women (mean age, 59.1 +/- 10.6 years) had not. Baseline characteristics -age, weight, height, BMI (greater than or = 25 or <25), follicle stimulating hormone, estradiol, and leptin values-were compared in the two groups. In a second analysis to evaluate the influence of HRT, estradiol concentrations, and BMI on leptin concentrations, these data were analysed in women allocated to one of four groups: (a) postmenopausal women not on HRT with a BMI <25 (n = 130); (b) postmenopausal women not on HRT with a BMI greater than or = 25 (n = 151); (c) postmenopausal women on HRT with a BMI<25 (n = 48); and (d) postmenopausal women on HRT with a BMI greater than or = 25 (n = 23). Leptin concentrations were subsequently analysed in relation to BMI and age and BMI and estradiol concentrations to determine any independent effect of these variables. RESULTS: The women taking HRT had a significantly lower mean age, weight, BMI and follicle stimulating hormone concentration than those who were not taking HRT. Furthermore, they had a higher mean height and serum estradiol value, but a significantly lower serum leptin concentration. After controlling for BMI, neither the use of HRT nor the estradiol concentration was found to be related to the leptin value (group (a) versus (c) and group (b) versus (d)), but there were significant differences in leptin concentrations between HRT users with BMI greater than or = 25 and BMI <25 and between women not taking HRT with BMI greater than or = 25 and BMI <25 (groups (a) versus (b) and (c) versus (d)). Furthermore, women with a BMI greater than or = 25 had significantly higher leptin concentrations than women with a BMI<25, irrespective of the HRT use. CONCLUSIONS: Leptin concentrations are significantly higher in obese postmenopausal women than in their non-obese counterparts. Serum leptin concentrations are not influenced by HRT use or estradiol concentrations. Further studies are needed to elucidate the role of HRT and estrogen on serum leptin concentrations.     

Comparison of leptin protein levels in Prader-Willi syndrome and control individuals

Prader-Willi syndrome (PWS) is characterized by early childhood obesity, mental deficiency, hypogonadism, hypotonia, hypopigmentation, short stature, small hands and feet, and a characteristic face. It is the most common genetic cause of obesity and obesity is the most significant health problem for PWS patients. Ob protein (leptin), which is produced by adipose tissue, is thought to play a significant role in obesity; thus, unusually low plasma leptin levels, or relative loss of sensitivity to leptin in PWS subjects, could be an important factor in their obesity. We measured plasma leptin levels in 19 obese and 14 non-obese PWS patients [mean body mass index (BMI) 37.2 and 22.0, respectively] and compared these levels to those of 28 obese controls (mean BMI 35.5) and 16 non-obese control individuals (mean BMI 21.6). The mean plasma leptin concentration (ng/ml) for obese PWS subjects was 33.4 and 23.6 for non-obese PWS subjects. Obese control leptin was 36.2 ng/ml and non-obese control was 9.9. Among the control groups, leptin levels in females were significantly higher than those in males; the obese males and females had significantly higher leptin than their respective non-obese counterparts. These differences did not hold true for the PWS subjects. Leptin levels in obese PWS males and females were similar, and the same was true of the non-obese PWS males and females. The differences between obese and non-obese PWS subjects of both sexes were small and not significant. Comparing control groups with their PWS counterparts revealed no significant differences, with one exception: circulating plasma leptin levels in non-obese PWS males were nearly five times higher than in non-obese control males with similar BMI. This difference may reflect a more female pattern of fat distribution and hypogonadism, which are characteristic of PWS males. Leptin levels in PWS patients were not obviously correlated with the chromosome 15 finding seen in the patients. Am. J. Med. Genet. 75:7–12, 1998. © 1998 Wiley-Liss, Inc.     

血清瘦素水平变化对围绝经期妇女脂类代谢的影响

探讨瘦素与围绝经期妇女肥胖及脂类代谢的关系.本文分别测量了110例围绝经期妇女(疾病组)血清瘦素(Leptin)、胰岛素(INS)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、载脂蛋白A1(apoA1)、载脂蛋白B(apoB)、垂体促性腺激素(LH、FSH)、雌二醇(E2)、睾酮(T)、孕酮(P)及体重和身高.与60名正常育龄妇女(对照组)进行比较分析.结果表明围绝经期肥胖组、非肥胖组血清Leptin、INS水平增高与对照组比较其差异有显著意义(P＜0.01).肥胖组LDL-C 5.01mmol/L、TG 2.21mmol/L、apoB 0.89g/L与非肥胖组及对照组相比,其差异有显著意义(P＜0.01).研究组内LH、FSH、E2和T值,差异无显著意义(P＞0.05),但与对照组比较,差异有显著意义(P＜0.01).相关分析显示:围绝经期妇女Leptin与BMI、INS、LDL-C、apoB高度相关(r=0.762,P=0.002;r=0.382,P=0.01,r=0.430,P=0.002;r=0.545,P=0.001; r=0.454,P=0.001),且LDL-C与apoB同步升高在明显相关(r=0.796,P=0.001).围绝经期瘦素水平与HDL-C、apoA1分析未见相关(r=-0.222～-0.190,P＞0.05).围绝经期Leptin水平与脂类代谢异常相关,肥胖、Leptin增高围绝经期妇女更应重视脂类代谢异常.     

Baseline non-fasting serum leptin concentration to body mass index ratio is predictive of IVF outcomes

BACKGROUND: The present study was designed to determine whether circulating leptin concentrations and/or body mass index (BMI) in women undergoing IVF are predictive of outcomes. METHODS: IVF cycle outcomes, e.g. fertilization, embryo development, implantation, pregnancy, were analysed relative to baseline (i.e. day gonadotrophin stimulation was initiated) non-fasting serum leptin concentrations and BMI. RESULTS: Serum leptin concentrations correlated with BMI (r = 0.739, P < 0.0001) as expected. Multiple logistic regression analyses showed correlation between serum leptin and pregnancy success (likelihood ratio = 5.198, P < 0.05), but there was no association between pregnancy and BMI. However, the serum leptin to BMI ratio was more strongly correlated (likelihood ratio = 7.258, P < 0.01) with pregnancy success than was leptin alone. Moreover, women with a low leptin:BMI ratio (< or =0.3) had significantly more superior quality embryos on day 3 post-retrieval (2.5 versus 1.4, P < 0.05, Kruskal-Wallis) and a greater implantation rate (26.7 versus 13.2%, P < 0.025, chi(2)) than women with a high leptin:BMI ratio (> or =0.7). CONCLUSIONS: The leptin:BMI ratio appears to be highly predictive of IVF success. Elevated leptin concentrations, particularly relative to BMI, may negatively impact fertility by assisted reproduction, possibly through direct ovarian actions resulting in impaired oocyte quality and/or early embryo development.     

Associations between total body fat and serum lipid concentrations in obese human adolescents

To investigate the relationships between obesity and serum lipid concentrations, we measured eight anthropometric parameters, body mass index (BMI), total body fat (TBF), and serum lipid profiles in 790 apparently healthy adolescents. TBF was assessed using a body fat analyzer. Serum concentrations of triglyceride, total cholesterol, and low- or high-density lipoprotein-cholesterol (LDL-C or HDL-C) were determined by standard enzymatic procedures. There were no significant differences in serum lipid concentrations between obese adolescents (BMI > or = 95th percentile) and lean adolescents (BMI < 5th percentile), nor between overweights (BMI > 25 kg/m2) and underweights (BMI < 19 kg/m2). However, serum lipid concentrations were significantly higher in males with TBF > 37% (TBF > 95th percentile) than in males with TBF < 6% (TBF < 5th percentile; p < 0.01). Serum lipid concentrations were more strongly correlated with TBF than with BMI. Correlation coefficients between serum lipid concentrations and TBF were higher in males than in females for cholesterol (r = 0.37 vs 0.23), triglycerides (r = 0.29 vs 0.27), HDL-C (r = -0.34 vs 0.12), and LDL-C (r = 0.24 vs 0.15). In short, compared to BMI, TBF reflects serum lipid concentrations more closely. During adolescence, the association between TBF and serum lipid concentrations is stronger in males than in females.     

血清Leptin在2型糖尿病、肥胖发病机制中的临床价值

目的：研究2型糖尿病血清Leptin与胰岛素,体脂分布和睾酮的关系。方法：对65例2型糖尿病患者及42例正常对照者用放免法测定血清Leptin及胰岛素。34例糖尿病患者进行75克葡萄糖耐量试验,32例行螺旋CT SSD技术测定体脂分布。30例男性糖尿病患者测定血清睾酮。结果：在调整了BMI（体重指数）,性别后,糖尿病组与对照组血清Leptin无差异。女性血清Leptin为男性的2．3倍,餐后2小时血清Leptin较空腹下降为19．19％,代谢控制不良者（空腹血糖＞14mmol)Leptin水平较低。性别,BMI,ASF（腹部皮下脂肪）是影响血清Leptin的重要因素,Leptin浓度与体重指数,胰岛素,腹部皮下脂肪显著正相关,与睾酮负相关,结论：2型糖尿病患者无异常血清Leptin,提示Leptin并非致2型糖尿病的主要因素,代谢控制不良者有Leptin缺乏,男性较低的Leptin可能与睾酮有关,性别,体重指数,腹部皮下脂肪是影响Leptin的主要因素。     

Maternal Serum and Cord Blood Leptin Concentrations at Delivery in Normal Pregnancies and in Pregnancies Complicated by Intrauterine Growth Restriction

IntroductionLeptin is a polypeptide hormone, and in pregnancy, it is secreted by the placenta and maternal and fetal adipose tissues. Normal leptin production is a factor responsible for uncomplicated gestation, embryo development, and fetal growth. The study compared maternal serum and cord blood leptin concentrations at delivery in normal pregnancies and in pregnancies complicated by intrauterine growth restriction (IUGR).MethodsThe study was performed in 25 pregnant women with isolated IUGR and in 194 pregnant women without any complications. Leptin concentrations in maternal serum and in cord blood samples collected at delivery were measured by ELISA and subsequently analyzed by maternal body mass index (BMI), mode of delivery, and infant gender and birth weight. For comparative analyses of normally distributed variables, parametric tests were used, that is, the Student t test and a one-way ANOVA. The nonparametric Mann-Whitney test was used when the distribution was not normal. The Pearson correlation coefficient was calculated to assess the correlation between normally distributed variables (p < 0.05).ResultsIn pregnancies complicated by IUGR, the mean maternal serum leptin concentration at delivery was significantly higher (52.73 ± 30.49 ng/mL) than in normal pregnancies (37.17 ± 28.07 ng/mL) (p = 0.01). The mean cord blood leptin concentration in pregnancies complicated by IUGR was 7.97 ± 4.46 ng/mL and significantly lower than in normal pregnancies (14.78 ± 15.97 ng/mL) (p = 0.04). In normal pregnancies, but not in pregnancies complicated by IUGR, a statistically significant correlation was established between maternal serum leptin concentrations and maternal BMI at delivery (r = 0.22; p = 0.00). No statistically significant correlation was found between cord blood leptin concentrations and maternal BMI in either study subjects or controls. In normal pregnancies, but not in pregnancies complicated by IUGR, a strong correlation was observed between cord blood leptin concentrations and birth weight (r = 0.23; p = 0.00).ConclusionsElevated maternal blood leptin concentrations in pregnancies complicated by IUGR may indicate a significant adverse effect of elevated leptin on fetal growth. The differences in leptin concentrations, measured in maternal serum and in cord blood, between the study subjects and controls suggest that deregulated leptin levels may increase the risk of obstetric complications associated with placental insufficiency.     

Leptine participation in the development of liver steatosis and biliar lithiasis

Obesity increases significantly the risk of developing several common gastrointestinal diseases such as gallstone disease (GD) and hepatic steatosis (HS). Elsewhere we have shown a relationship between HDL cholesterol, cholesterol saturation index, and leptin in obese patients loosing weight. Furthermore, leptin plays an important role facilitating HS and possibly in the associated inflammatory process. The aim of this study was to investigate the relationship between GD and HS. The sample was comprised by patients attending the unit for check-up. Subjects with visible stones or HS by ultrasound (cases) were compared with healthy controls. Demographic and body mass index (BMI) were recorded. Plasma leptin, insulin and serum lipids and lipoproteins levels were measured by standard methods. A total of 317 subjects were included in this study. They were divided in four groups as follows: GD (n=100), HS (n=84), GD + HS (n=33) and controls (n=100). The control group was significantly older (GD, 52.6+/-11.6; HS, 49.8+/-11.1; GD +HS, 51.6+/-10.5; 57.1+/-7.4), p< 0.05. BMI was higher in the HS groups (28.7 +/- 2.8) and GD +EH (29.0 +/- 3.8) than in the GD (27.4 +/- 4.3) and control (27.0 +/- 3.1) group, p<0.05. The GD group displayed the highest leptin levels (13.7 241 8.1), P < 0.05, whereas insulin levels were similar in all groups. Since GD and HS subjects have high plasma leptin levels compared with controls, our results suggest that leptin plays an important role in the pathophysiology of GD and HS.