儿童单纯性肥胖血清瘦素水平分析

目的：比较单纯性肥胖儿童与正常健康儿童血清瘦素的水平，分析血清瘦素与空腹胰岛素之间的关系。方法：选择单纯性肥胖儿童30例，健康非肥胖儿童30例作对照组，分别测定其空腹胰岛素与瘦素水平。结果：单纯性肥胖组血清瘦素明显高于对照组（P＜0．001），瘦素与空腹胰岛素呈显著性相关（r=0.854，P＜0．001）。结论：单纯性肥胖儿童体内存在高胰岛素血症，同时存在瘦素抵抗，胰岛素与瘦素的调控是双向的。     

单纯性肥胖儿童骨龄与体质量指数及性激素水平的相关性

目的 检测单纯性肥胖儿童的骨龄和性激素水平,分析骨龄与体质量指数(BMI)和性激素水平之间的关系.方法 选取40例单纯性肥胖患儿(肥胖组)及40例体检健康儿童(健康对照组).常规测量二组儿童身高和体质量,并计算BMI.采用G-P图谱法对左手腕指关节正位片进行骨龄评定;采用罗氏E170化学发光免疫分析仪测定二组儿童血清雌二醇、睾酮水平.比较二组儿童骨龄、BMI和性激素水平间的差异,并对骨龄与BMI及性激素水平进行相关性分析.结果 肥胖组骨龄[(11.85±2.76)岁]、BMI[(27.26±5.16) kg·m-2]及雌二醇[(29.20±11.61) pmol·L-1]均显著高于健康对照组[(10.57±2.59)岁,(16.75±4 73) kg·m-2,(22.35±10.87) pmol·L-1](t=10.57、9.50、2.72,P<0.05、0.01、0.01);肥胖组睾酮[(0.07±0.04) μg·L-1]显著低于健康对照组[(0.10±0.05) μg·L-1](t=2.96,P<0.01).肥胖组骨龄与BMI、雌二醇均呈显著正相关(r=0.696、0.773,Pa<0 05);与睾酮呈负相关(r=-0.726,P<0.05).结论 单纯性肥胖儿童的骨龄较同龄健康儿童超前,骨龄超前与体内雌激素水平有关,雌二醇水平的升高可能是导致单纯性肥胖儿童骨龄超前的主要原因.     

肥胖女童血清雌二醇、瘦素含量测定

目的　了解单纯性肥胖女童体内瘦素、雌二醇 (E2 )水平 ,分析瘦素对E2 分泌的影响 ,为儿童少年保健工作提供理论依据。方法　选定单纯性肥胖女童、体质量正常女童各 6 0例 ,年龄 8～ 15岁。放射免疫法测定血清瘦素、E2 含量 ;问卷法调查月经初潮年龄。结果　单纯性肥胖女童血清瘦素水平随年龄增长而升高 ;肥胖女童血清瘦素 [(34.2 0± 13.92 ) μg/L]显著高于体质量正常女童 [(9.0 0± 3.0 6 ) μg/L](P <0 .0 1) .肥胖女童血清E2 水平也随年龄增长而升高 ,但在青春期前高于正常组 ,而在青春期却低于正常组。瘦素与E2 含量呈负相关(r =- 0 .5 4　P <0 .0 1)。肥胖女童月经初潮年龄早于正常组。结论　肥胖女童血清瘦素水平偏高 ,E2 水平在青春期偏低 ,瘦素可能对卵巢分泌E2 的功能有抑制作用     

瘦素抵抗及其受体基因变异对单纯性肥胖患儿脂代谢的影响

目的探讨瘦素受体(LEPR)基因外显子突变与瘦素抵抗对单纯性肥胖患儿脂代谢的影响。方法选取6～14岁单纯性肥胖患儿102例(肥胖组)及非肥胖儿童83例(对照组)为研究对象,空腹12 h后抽取2组儿童外周静脉血,常规抽提基因DNA,用PCR限制性片断长度多态性及聚丙烯酰胺凝胶电泳法对2组儿童LEPR基因的第20外显子基因变异频率进行分析,采用放射性免疫分析法测定其血清瘦素水平及血清三酰甘油(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)水平及2组儿童身高和体质量。结果共检出3种LEPR基因第20外显子的基因型:AA型、AG型、GG型;与对照组儿童比较,单纯性肥胖患儿LEPR基因第3 057位核苷酸G→A突变率增高。AA基因型的肥胖患儿血清TC、TG、LDL-C水平均明显高于GG型者,而HDL-C水平低于后者。与对照组比较,肥胖组患儿存在血脂代谢紊乱,血清瘦素水平增高,79%存在瘦素抵抗。瘦素抵抗组患儿血清TC、TG、LDL-C显著高于瘦素敏感组,HDL-C低于瘦素敏感组。基因型为AA的瘦素抵抗者与基因型为GG的瘦素抵抗者比较,血清TG、LDL-C水平升高,HDL-C水平降低(Pa<0.05)。结论单纯性肥胖患儿存在瘦素抵抗及LEPR基因第20外显子基因突变,二者可影响儿童脂质代谢,且有一定的协同作用。临床表现为LEPR基因第20外显子AA基因型的瘦素抵抗个体更易发生血脂代谢紊乱。     

单纯性肥胖儿童血清胰岛素样生长因子-1水平的临床研究

目的探讨单纯性肥胖儿童是否存在胰岛素样生长因子-1(insulinlikegrowthfactor1,IGF1)水平的异常,为防治儿童单纯性肥胖开辟新的医学途径。方法检测并分析50例单纯性肥胖儿童、30例健康儿童血清胰岛素、IGF1水平及血压。结果与健康儿童比较,单纯性肥胖儿童血清胰岛素、收缩压、舒张压增高,差异有显著性(P<0.05)。肥胖的程度不同,血糖、胰岛素、IGF1水平亦不同。对照组、轻、中、重度肥胖组的血糖、胰岛素、IGF1水平差异有统计学意义(F=8.79～14.82,P均<0.05)。重度肥胖组儿童的血糖浓度高于对照组和轻度肥胖组(P<0.05),而IGF1水平低于其他三组;中、重度肥胖儿童血清胰岛素水平高于对照组及轻度肥胖组(P<0.05);单纯性肥胖儿童血压高于健康儿童(P<0.05),高胰岛素血症的肥胖儿童血压明显高于胰岛素正常的儿童(P<0.01)。高胰岛素血症肥胖儿童IGF1水平低于胰岛素正常的儿童(P<0.01)。结论单纯性肥胖儿童,尤其是重度肥胖儿童,存在高胰岛素血症、高血压、IGF1水平低下及高血糖;IGF1水平下降是单纯性肥胖儿童物质代谢紊乱的危险信号,是肥胖儿童未来心血管疾病、糖尿病等的又一危险因素。     

瘦素/脂联素值与肥胖儿童体质量指数及糖脂代谢的关系

目的 探讨瘦素/脂联素(L/A)值与单纯性肥胖儿童体质量指数(BMI)、糖脂代谢及肥胖症发病的关系.方法 单纯性肥胖60例和57例健康儿童,采用放射免疫分析(RIA)法测定其血清瘦素水平;ELISA法测定其血清脂联素、空腹胰岛素(FINS)水平;免疫比浊法测定其血脂各成分.分析并比较血清瘦素、脂联素及L/A值与肥胖儿童BMI、糖脂代谢的相关性.结果 1.肥胖儿童血清瘦素、FINS和三酰甘油(TG)水平与健康对照组相比明显增加;脂联素水平降低,差异均有显著性(Pa＜0.05,0.01).2.单纯性肥胖儿童瘦素与BMI、FINS、TG水平均呈显著正相关(r=0.408,0.301,0.301 Pa＜0.05,＜0.01);脂联素水平与BMI、FINS、TG均呈显著负相关(r=-0.360,-0.413,-0.258 Pa＜0.01,＜0.05).3.L/A值与BMI、FINS、TG呈显著正相关(r=0.780,0.764,0.601 Pa＜0.001).结论 血清瘦素和脂联素与肥胖儿童的发病有关,可作为儿童肥胖的监控指标;L/A值较单独瘦素、脂联素更能反映肥胖症儿童的代谢状况,可为肥胖症儿童糖脂代谢提供更为有效的监测指标.     

甲状腺功能异常患儿血清瘦素水平与甲状腺激素的相关性研究

目的　研究甲状腺功能异常 [原发性甲状腺功能减退 (甲减 )和原发性甲状腺功能亢进 (甲亢 ) ]患儿血清瘦素 (leptin)水平变化 ,探讨血清瘦素与甲状腺功能的关系。方法　采用放射免疫法分别检测 2 0例甲减患儿、17例甲亢患儿和 2 5例健康儿童血清瘦素水平 ,同时采用微粒子化学发光免疫分析法检测血清游离三碘甲状腺原氨酸 (FT3 )、游离甲状腺素 (FT4)、促甲状腺素 (TSH)等指标。结果　甲低组治疗前血清瘦素水平显著低于正常对照组 (P <0 .0 0 1) ,经药物治疗甲状腺功能恢复至正常后 ,其血清瘦素浓度上升至正常水平 ;甲亢组治疗前后血清瘦素水平与正常对照组相比 ,差异无显著性 (P >0 .0 5 )。结论　甲状腺激素对血清瘦素的分泌具有促进作用     

单纯性肥胖男童血清瘦素、性激素水平及其对性发育的影响

目的 探讨单纯性肥胖男性儿童血清瘦素、性激素水平及其对性发育的影响.方法 从8～14岁1 208例小学生中筛选出体质量指数(BMI)≥25 kg/m2的42例男童作为肥胖组,选择BMI 14.1～23.0 kg/m2的健康男童32例作为健康对照组,对所入选儿童用ELISA法测定其血清瘦素,放射免疫分析法测定其血清雌二醇(E2)、睾酮(T)水平,用游标卡尺测量其阴茎长度及睾丸体积.采用SPSS 10.0软件行组间t检验比较二组差异,直线相关分析单纯性肥胖儿童血清瘦素与E2、T的相关性.结果 肥胖组男童血清瘦素为(16.82±11.46)μg/L,较健康对照组(5.43±3.56)μ/L显著增高,二组比较有显著性差异(t=5.419 P<0.01).肥胖组男童血清E2水平为(20.51±16.42)ng/L,较健康对照组[(8.84±4.53)ng/L]显著增高,二组比较有显著性差异(t=3.903 P<0.01).肥胖组男童T水平为(1.64±0.85)μg,/L,低于健康男童[(2.07±0.98)μ/L],二组比较有显著性差异(t=2.018 P<0.05).肥胖组男童阴茎长度为(4.51±1.36)cm,低于健康男童[(5.64±0.99)cm],二组比较有显著性差异(t=3.965 P<0.01).肥胖组男童睾丸体积[(4.21±2.32)cm3]低于健康男童[(7.08±3.76)cm3],二组比较有显著性差异(t=4.043 P<0.01).瘦素与BMI、E2呈正相关(r=0.757,0.266 Pa<0.05),与T呈负相关(r=-0.368 P<0.01).结论 高水平瘦素可能是单纯性肥胖重要的生物学标志之一.单纯性肥胖男童存在性激素代谢紊乱、性发育落后,瘦素可能影响男性肥胖儿童的性发育.     

罗格列酮对肥胖大鼠外周瘦素抵抗的影响

目的观察高脂喂养的肥胖大鼠模型瘦素抵抗出现的时间、程度、在肥胖形成过程中的动态变化及与胰岛素抵抗的关系;探讨罗格列酮对高脂肥胖大鼠瘦素抵抗的影响.方法清洁级雄性Wistar大鼠30只按体质量随机分成正常对照组、肥胖组和治疗组.肥胖组和治疗组以高脂饮食喂养20周,制备肥胖模型.治疗组于20周后予以罗格列酮2 mg/(kg·d)灌胃.于实验过程第10、20、24周分别取血检测空腹血糖、空腹胰岛素和血清瘦素.结果肥胖组大鼠血清瘦素水平明显高于正常组、治疗组(P均<0.05);正常组与治疗组无显著差异.肥胖组血清瘦素水平逐渐升高,第20周显著高于第10周(P<0.01).血清瘦素与血清胰岛素水平(r=0.427 P<0.05)、三酰甘油(r=0.515 P<0.01)呈显著正相关.结论肥胖存在瘦素抵抗.瘦素抵抗与胰岛素抵抗密切相关,血清瘦素水平是代谢综合征和心血管疾病发展的预报器.罗格列酮治疗在改善胰岛素抵抗的同时,也降低瘦素抵抗的水平.     

性早熟女童性激素、瘦素水平及其影响因素

目的了解中枢性性早熟女童基础性激素、瘦素水平及相关影响因素。方法以78例中枢性早熟女童为研究对象,同时选择78例非性早熟女童为对照组,精确测量两组女童的身高、体质量,按G-P图谱测评骨龄,并取晨起空腹血清检测性激素及瘦素水平。采用t检验、秩和检验和Spearman相关分析进行统计学分析。结果性早熟女童的身高、体质量、骨龄、体质指数(BMI)、瘦素、促性腺激素(LH和FSH)、雌二醇(E2)水平均高于对照组女童;性早熟女童瘦素水平与LH、FSH、骨龄呈正相关,对照组瘦素与性激素水平无相关性;与骨龄相比,瘦素与LH、FSH的相关性较强。结论中枢性性早熟女童有明显的体格发育与基础性激素水平改变,瘦素对性早熟的发生起重要作用。     

Thyroid hormones before and after weight loss in obesity

Background: Little is known about changes in thyroid function in obese children. An influence of leptin on thyroid hormone synthesis has been proposed. Aims: To examine thyroid function and leptin concentrations in obese children. Methods: Triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), and leptin were measured in 118 obese children (aged 4.5–16 years); thyroid function was also determined in 107 healthy children of normal weight. T3, T4, and TSH were analysed in 55 obese children who had achieved weight reduction and in 13 obese children who had not achieved weight reduction after one year based on normal energy diet. Results: TSH, T3, and T4 were significantly higher in obese children compared to those of normal weight. Twelve per cent of the obese children had TSH, 15% had T3, and 11% had T4 concentrations above the twofold standard deviation of normal weight children. The degree of overweight correlated with T3, T4, and TSH. Thyroid hormones did not correlate significantly with leptin. A reduction in overweight showed a significant decrease in T3, T4, and leptin serum concentrations, but there was no significant change in TSH. Conclusion: Peripheral thyroid hormones (T3, T4) and TSH are moderately increased in obese children; weight reduction leads to a long term decrease in the peripheral thyroid hormones but not in TSH. There is no necessity to treat the increased serum TSH.     

Thyroid hormones before and after weight loss in obesity.

BACKGROUND: Little is known about changes in thyroid function in obese children. An influence of leptin on thyroid hormone synthesis has been proposed. AIMS: To examine thyroid function and leptin concentrations in obese children. METHODS: Triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), and leptin were measured in 118 obese children (aged 4.5-16 years); thyroid function was also determined in 107 healthy children of normal weight. T3, T4, and TSH were analysed in 55 obese children who had achieved weight reduction and in 13 obese children who had not achieved weight reduction after one year based on normal energy diet. RESULTS: TSH, T3, and T4 were significantly higher in obese children compared to those of normal weight. Twelve per cent of the obese children had TSH, 15% had T3, and 11% had T4 concentrations above the twofold standard deviation of normal weight children. The degree of overweight correlated with T3, T4, and TSH. Thyroid hormones did not correlate significantly with leptin. A reduction in overweight showed a significant decrease in T3, T4, and leptin serum concentrations, but there was no significant change in TSH. CONCLUSION: Peripheral thyroid hormones (T3, T4) and TSH are moderately increased in obese children; weight reduction leads to a long term decrease in the peripheral thyroid hormones but not in TSH. There is no necessity to treat the increased serum TSH.     

Relationship between plasma leptin, insulin and tumor necrosis factor alpha in obese children

OBJECTIVES: 1. To evaluate the relationship between plasma leptin and TNFalpha concentrations in obese children and to assess the differences between hyperinsulinemic and normoinsulinemic groups. 2. To evaluate the relationship between plasma leptin and insulin levels in obese children. 3. To investigate the TNFalpha G308A mutation in obese children. METHODS: Body mass index (BMI), fasting plasma glucose and insulin levels, oral glucose tolerance test results, homeostasis model assessment of insulin resistance (HOMA-IR) results, and plasma leptin and TNFalpha concentrations were evaluated in obese children (n = 45) and age- and gender-matched, lean healthy controls (n = 40). RESULTS: In obese children the fasting insulin, HOMA-IR results, plasma leptin and TNFalpha concentrations were significantly higher than in controls (p <0.05). Furthermore, obese females showed higher plasma leptin and insulin resistance compared to obese males. While plasma leptin, TNFalpha levels and HOMA-IR results were similar in the prepubertal and pubertal groups, insulin levels were significantly higher in the pubertal group. Plasma leptin and TNFalpha concentrations were similar in hyperinsulinemic and normoinsulinemic obese children. In control children, plasma leptin concentrations showed a positive correlation with BMI, age, fasting insulin and HOMA-IR results. In obese children, plasma leptin levels did not correlate with BMI, fasting insulin or TNFalpha. CONCLUSION: Plasma leptin concentrations did not show any correlation with TNFalpha levels in obese children. Furthermore, plasma leptin and TNFalpha concentrations were similar in hyperinsulinemic and normoinsulinemic obese children.     

Serum leptin level in prepubertal children with simple obesity. Part II

The aim of the study was to determinate the serum leptin level, glucose concentration, lipids (total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride) and thyroid hormones level (triiodothyronine, thyroid stimulating hormone and free thyroxine) in a group of prepubertal children with simple obesity. Fourfold higher leptin concentration in obese (23.3 +/- 11.8 ng/mL) in comparison to a group of slim children (6.8 +/- 2.7 ng/mL), (p<0.0001) was shown. There was no significant difference in serum glucose level (87.3 +/- 9.7 mg/dL) between both studied groups. In obese subjects we showed higher triglyceride, insignificantly lower HDL-C concentrations and invariable other lipid fractions. Mean values of triiodothyronine (T3) were 3.0 +/- 0.7 nmol/L in obese children and 2.8 +/- 0.8 nmol/L in slim children. On the contrary, mean values of thyroid stimulating hormone (TSH) were 2.5 +/- 1.7 mIU/L and 2.8 +/- 0.7 mIU/L in the group of obese and normal children respectively. Free thyroxine (FT4) concentrations in our obese children were lower (11.5 +/- 2.9 pmol/L) than in slim subjects (14.6 +/- 3.1 pmol/L) but were within the reference range. The results obtained indicate that in children with simple obesity there was no dyslipidemia connected with leptin and thyroid hormones levels. However, higher triglyceride and lower HDL-C concentrations suggest a necessity of monitoring the body mass index and lipid profile in these patients.     

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目的观察单纯性肥胖儿童和健康正常体重儿童血清脑源性神经营养因子(BDNF)质量浓度的差异,探讨BDNF与儿童肥胖及瘦素抵抗、胰岛素抵抗的关系。方法南京军区福州总医院儿科等于2004年5月至2005年5月应用酶联免疫法检测单纯性肥胖儿童(37例)和健康儿童(31例)血清BDNF质量浓度与胰岛素(INS)浓度,应用放射免疫法检测血清瘦素(LEP)质量浓度。比较两组儿童血清BDNF、INS、LEP的差异,分析血清BDNF质量浓度与血清LEP质量浓度和INS浓度的关系。结果(1)两组儿童的体重指数(BMI)、BDNF、INS及LEP均差异显著(BMI:F=175·05,P<0·01;BDNF:F=12·35,P<0·01;INS:F=21·71,P<0·01;LEP:F=48·89,P<0·01),肥胖组BMI、INS及LEP均明显高于健康组,而肥胖组BDNF明显低于健康组。(2)影响LEP的因素依次为BMI、丙氨酸转氨酶(ALT)、BDNF(R2=0·5946,F=0·31,P<0·01);影响INS的因素依次为BMI、BDNF(R2=0·2647,F=11·34,P<0·01)。去除BMI、ALT影响后,BDNF与LEP、INS负相关(BDNF与LEP:r=-0·2455,P<0·05;BDNF与INS:r=-0·2878,P<0·05)。结论(1)肥胖儿童血清BDNF缺乏,未发现“BDNF抵抗”的特点。(2)学龄前儿童血清LEP、INS受BMI影响最大,还受血清BDNF影响。BDNF是二者独立的负相关因素。     

Changes in leptin, insulin and body composition in obese children during a weight reduction program

BACKGROUND: Girls have higher leptin concentrations than boys at all stages of biological development and this is also seen in the state of obesity. Little is known about whether gender and biological development of obese children influence changes in leptin associated with a short-term weight reduction program. OBJECTIVE: To study whether leptin concentration, body composition and insulin levels in obese children were influenced by a 3-week intervention program including diet and sports. STUDY DESIGN: Sixty-two obese children (32 boys and 30 girls) were examined before and after the intervention program. Body composition was measured by bioelectrical impedance and BMI-SDS was calculated. Serum leptin and serum insulin were determined by RIA. RESULTS: Girls had higher leptin levels than boys, before and after the weight reduction program. Body mass, fat mass (FM), leptin and insulin were decreased after the intervention in both sexes. We found a greater change in serum leptin in girls but the change in FM was of greater magnitude in boys. However, percentage changes in leptin were not significantly different between the sexes. Before the intervention, leptin concentrations were correlated with %FM, FM and moderately with BMI-SDS in all children. Only in pubertal boys did correlation of leptin with %FM increase after the intervention (from r=0.57 to r=0.75, p<0.01). Changes in leptin were found to be associated with initial leptin values in boys (r=0.95, p<0.01) and in girls (r=0.93, p<0.01), independent of Tanner stages. CONCLUSION: Serum leptin levels were positively correlated with adiposity in obese children and a diet and sports intervention program decreased serum leptin, insulin and body fat in all children. Changes in leptin were best described by the initial leptin concentration. The increase in correlation of leptin with %FM in obese pubertal boys after the intervention could have its underlying mechanism in an increased sensitivity to leptin and anabolic hormones.     

肥胖儿童血清抵抗素变化及其临床意义

目的 探讨饮食控制和运动疗法对肥胖儿章血清抵抗素水平的影响及其临床意义。方法 测定36例肥胖儿童饮食控制和运动治疗前后血清抵抗素、胆固醇（CHO）、甘油三脂（TG）、低密度脂蛋白胆固醇（LDL-C）、空腹和葡萄糖耐量试验（OGTT）2小时血糖、胰岛素,计算胰岛素抵抗指数（HOMA-IR）。结果 肥胖儿童血清抵抗素水平显著高于对照组（P〈0．05）,并与OGTT2小时血糖、胰岛素呈正相关（P〈0．05）;经饮食控制和运动治疗后肥胖儿童血清抵抗素、体重、BMI、血清CHO、TG、LDL-C、空腹和OGTT2小时胰岛素、HOMA-IR显著低于治疗前（P〈0．05）,治疗前后空腹和OGTT2小时血糖差异无显著性（P〉0．05）。结论 肥胖儿童血清抵抗素水平升高,并与OGTT2小时血糖、胰岛素呈正相关,推测将来有可能以检测血清抵抗素水平来了解肥胖儿童有否存在糖耐量受损;饮食控制和运动疗法可使肥胖儿童血清抵抗素降低,胰岛素抵抗减轻。     

肥胖儿童瘦素水平的变化及其与骨密度的关系

目的：探讨长沙市肥胖儿童血清瘦素水平的变化及与骨密度（BMD）、身体成分的关系,为预防和治疗儿童肥胖及骨质疏松提供科学依据。方法：从长沙市5所小学随机抽取119例肥胖儿童和103例正常儿童,采用双能X线骨密度仪（DEXA）进行全身扫描,测定骨密度及身体成分;采用酶联免疫吸附试验（ELISA）测定血清瘦素水平。结果：①肥胖儿童的身高、体重、体重指数（BMI）、腰围和腰臀比均显著高于正常儿童（P<0.01）。②肥胖儿童的全身骨密度、骨矿物质含量、瘦组织含量、脂肪组织含量、体脂百分比(%BF)及血清瘦素水平均显著高于正常儿童（P<0.01）。③血清瘦素水平与儿童全身骨密度、骨矿物质含量、瘦组织含量、脂肪组织含量均呈显著正相关（r=0.528~0.903）,其中瘦素水平与脂肪组织含量呈高度正相关（男：r=0.883,女：r=0.903）。多元逐步回归分析显示,BMI及%BF是儿童血清瘦素水平的独立影响因素。结论：肥胖儿童血清瘦素水平升高,血清瘦素水平与骨密度及身体成分显著相关,BMI、%BF是儿童血清瘦素水平的独立影响因素。［中国当代儿科杂志,2009,11（9）：745-748］     

Leptin binding activity (LBA) in plasma of nondiabetic and diabetic adolescents and obese children: relation to auxologic and hormonal data

Leptin circulates in serum bound to high molecular weight proteins. Hypothesizing that leptin binding proteins may regulate the functional efficiency of leptin, we characterized auxologic and hormonal factors that influence leptin binding in three disparate groups: normal adolescents, obese children, and teenagers with type I diabetes mellitus (IDDM). Specific leptin binding activity (sLBA) was assessed by column chromatography after incubation of serum with 125I-leptin in the presence and absence of excess unlabeled leptin. Mean sLBA was 17.0 +/- 7% (SD) in the healthy adolescents (n=41), 6.6 +/-4.3% in the obese children (n=26), and 14.9 +/-7.3% in the diabetic teenagers (n=17). At any value of sLBA, obese children had higher serum leptin levels than non-obese adolescents or diabetic teenagers, consistent with "leptin resistance" in the obese group. sLBA was higher in males than in females only in those with diabetes (18.6 +/- 7.3 vs 10.9 +/- 5.1%, p<0.05). sLBA correlated inversely with serum insulin-like growth factor-I values in the normal group (r= -0.45, p<0.01) and with insulin in the obese children (r= -0.53, p<0.01). There was no correlation between sLBA or serum leptin values and HbA1c, in the diabetic group. The serum leptin concentration was the principal determinant explaining the total variability of sLBA in all three cohorts. However, body mass index (BMI = weight/ height2) accounted for more of the total variability of percent specific binding in the healthy adolescents than in the other groups. We conclude that sLBA reflects circulating leptin levels, body composition, and hormonal milieu. Thus, in addition to leptin, qualitative and quantitative characteristics of leptin binding may play a physiological role in the regulation of appetite and in the "leptin resistance" of obesity.