先天性心脏病患儿营养不良与生长激素-胰岛素样生长因子轴的关系

目的探讨先天性心脏病（CHD）患儿营养不良与生长激素-胰岛素样生长因子（GH-IGF）轴的关系。方法依据有无发绀及心力衰竭,将50例CHD患儿分为发绀组13例、非发绀组37例;非发绀组又分为2个亚组：心力衰竭组25例、无心力衰竭组12例。20例健康儿童作为健康对照组,通过测定各组儿童血总蛋白、清蛋白及测量身高、体质量来评价其营养状况;采用免疫放射分析方法来检测血IGF-Ⅰ、胰岛素样生长因子结合蛋白-3（IGFBP-3）及生长激素结合蛋白（GHBP）,并进行比较。结果CHD患儿急、慢性营养不良的发生率分别为62%和28%,急性营养不良的发生率发绀组与非发绀组相似（P=0.105）;慢性营养不良的发生率发绀组高于非发绀组（P=0.006）;各组CHD患儿血清IGF-Ⅰ、IGFBP-3水平均下降,其中发绀组及心力衰竭组下降更为显著;发绀组及心力衰竭组患儿血GHBP水平下降。结论CHD患儿血清IGF-Ⅰ和IGFBP-3水平下降,考虑与生长激素受体（GHR）有关,GHR下调可能是GH抵抗或不敏感的分子机制之一,而GH抵抗或不敏感是CHD患儿发生急、慢性营养不良的原因之一。     

特发性矮小患儿生长激素-胰岛素样生长因子轴变化的研究

目的 观察特发性矮小(ISS)患儿血中生长激素(GH)、胰岛素样生长因子-l(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)及生长激素结合蛋白(GHBP)水平的变化.方法 2002年6月至2006年5月在中南大学湘雅二医院儿科就诊的37例ISS患儿为病例组,37例年龄性别相匹配的正常儿童为对照组.采用放射免疫分析法(RIA)测定血清GH,免疫放射计量法(IRMA)测定血清IGF-1及IGFBP-3,葡聚糖覆盖炭末吸附法(DCT)检测血清GHBP.结果 ISS组血清GHBP、IGF-1、IGFBP-3均明显低于对照组(均P＜0.01),而血清GH基础值在ISS组明显高于时照组(P＜0.05).结论 ISS患儿血中IGF-1和IGFBP-3降低可能是其矮小的原因之一.ISS患儿血中反映生长激素受体(GHR)水平的GHBP降低,而GH基础值升高,提示可能存在因GHR缺陷导致的GH不敏感.     

甲状腺功能减退症患儿血清生长激素、胰岛素样生长因子-Ⅰ、胰岛素样生长因子结合蛋白-3水平的变化

目的通过监测甲状腺功能减退症患儿生长激素(GH)、胰岛素样生长因子-Ⅰ(IGF-Ⅰ)、胰岛素样生长因子结合蛋白-3(IGFBP-3)水平变化,探讨甲状腺功能减退症患儿GH-IGF轴与甲状腺素的变化规律。方法对56例甲状腺功能减退症(14例先天性甲状腺功能减退症和32例桥本病)患儿治疗前后血GH、IGF-Ⅰ、IGFBP-3水平和50例健康儿童血GH、IGF-Ⅰ、IGFBP-3水平进行监测。结果先天性甲状腺功能减退症新生儿9例患儿IGF-Ⅰ、IGFBP-3水平显著降低,经治疗后甲状腺功能逐渐恢复正常;5例先天性甲状腺功能减退症患儿和32例桥本病患儿无显著变化。结论先天性甲状腺功能减退症患儿存在GH-IGF轴功能紊乱,是导致身材矮小的重要原因,早期予甲状腺素治疗有利于维持患儿正常生长发育。     

矮小儿童下丘脑-垂体及其胰岛素样生长因子轴功能检查的意义

目的检测矮小儿童下丘脑-垂体及其胰岛素样生长因子(IGF-1)生长轴(GHRH-GH-IGF-1)功能,了解矮小儿童的发病因素及确定下丘脑-垂体及其IGF轴功能缺陷病因分类。方法矮小儿童30例。用统一印制的矮小儿童表格记录其临床特征。对矮小儿童进行甲状腺功能测定;用胰岛素 左旋多巴行生长激素(GH)刺激试验;放射免疫法测定血清IGF-1和血清胰岛素样生长因子结合蛋白-3(IGFBP-3)水平;同时行患儿骨龄、垂体增强MRI扫描、染色体核型分析、性激素测定。根据矮小症诊断标准和2004年Rosenfeld RG和GHRH-GH-IGF-1轴缺陷不同,将矮小儿童进行病因定位和分类。结果矮小儿童30例中,下丘脑-垂体及其IGF轴功能缺陷12例,占40%,其中肯定生长激素缺乏(GHD)4例,怀疑生长激素不敏感综合征2例,可疑GHD 6例。Turner′s综合征2例,占6.67%;体质性青春期延迟2例,占6.67%;特发性矮小14例,占46.6%。磁共振发现垂体微腺瘤2例;垂体发育不良12例。结论1.矮小儿童所占比例最大的为特发性矮小,其次为下丘脑-垂体及其IGF轴功能缺陷。2.IGF-1水平和IGFBP-3水平与生长激素刺激试验测定生长激素水平不一致,考虑存在生长激素抵抗和受体缺陷。3.矮小儿童可能存在先天性垂体发育异常,致使垂体分泌生长激素不足。     

左向右分流型先天性心脏病合并心力衰竭患儿血清IGF-1和IGFBP-3的变化及意义

目的：探讨左向右分流型先天性心脏病（先心病）合并心力衰竭（心衰）患儿血清胰岛素样生长因子-1（IGF-1）和胰岛素样生长因子结合蛋白-3(IGFBP-3)的变化及意义。方法：20例健康儿童（对照组）,20例无心脏基础疾病的心衰患儿（心衰组）,20例无心衰的左向右分流型先心病患儿（先心组）,30例伴心衰的左向右分流型先心病患儿（先心+心衰组）作为研究对象。对不同组别的血清IGF-1及IGFBP-3进行比较;并对先心+心衰组患儿按心功能Ⅱ、Ⅲ、Ⅳ级分为3个亚组,对其血清IGF-1、IGFBP-3及cTnI水平进行比较及相关性分析。结果：先心组血清IGF-1及IGFBP-3水平下降,与对照组比较差异有统计学意义(P<0.01)。先心+心衰组血清IGF-1水平明显下降,与对照组及先心组比较差异有统计学意义(分别P<0.01,P<0.05)。心衰组血清IGF-1及IGFBP-3水平明显增高,与其他各组比较差异有统计学意义(P<0.01)。先心+心衰组患儿按心功能分级比较的各亚组间随心功能下降血清IGF-1水平依次降低(P<0.01),且该组患儿血清IGF-1、IGFBP-3水平与血清cTnI水平呈负相关（分别r=-0.692、-0.530,P<0.05）。结论：血清IGF-1水平可作为左向右分流型先心病病情评估的客观指标及合并心衰的危险因素,这也为该类患儿使用外源性IGF-1治疗心衰提供了临床依据。     

胰岛素样生长因子-1受体基因与特发性矮小相关性研究进展

生长激素-胰岛素样生长因子(GH-IGF)轴是调节儿童生长发育中最重要的神经内分泌轴.胰岛素样生长因子-1受体( IGF-1 R)是调节该轴的激素受体级联反应的效应分子,它的分子结构或功能异常,将影响靶基因IGF-1与其结合,从而引起生长障碍,可能与特发性矮小(ISS)发生有一定关系.国内外尚无IGF-1R基因与ISS的研究,为探讨其与ISS的关系,现就近年来有关IGF-1 R与人体生长障碍的研究作简要综述.     

不同胎龄儿脐血IGF-1、IGFBP-1及CP水平的变化

目的 了解胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-1(IGFBP-1)及C肽(CP)对不同胎龄新生儿出生体重的影响。方法 选取不同胎龄的新生儿共76例,按孕周分为≤32、-34、-36、-38、-40、-42周6组,均为适于胎龄儿。分娩时取脐静脉血3 ml,用EIASA法测定血清IGF-1、IGFBP-1及CP。结果 自32周至40周,血清IGF-1、CP逐渐增加,IGFBP-1逐渐下降,各组间差异有显著意义(除34与36周三者比较P>0.05外),但至42周时,IGF-1、CP开始下降,IGFBP-1上升,与40周相比,P<0.05。IGF-1、CP均与胎龄呈中度正相关,而IGFBP-1与胎龄呈高度负相关。结论IGF-1、CP能促进孕晚期胎儿宫内生长,而IGFBP-1则对胎儿生长起抑制作用。因此,营养物质-胰岛素-胰岛素样生长因子系统代谢轴是孕后期调节胎儿生长的重要系统。     

不同胎龄儿脐血IGF-1、IGFBP-1及CP水平的变化

目的了解胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-1(IGFBP-1)及C肽(CP)对不同胎龄新生儿出生体重的影响.方法选取不同胎龄的新生儿共76例,按孕周分为≤32、～34、～36、～38、～40、～42周6组,均为适于胎龄儿.分娩时取脐静脉血3ml,用ELISA法测定血清IGF-1、IGFBP-1及CP.结果自32周至40周,血清IGF-1、CP逐渐增加,IGFBP-1逐渐下降,各组间差异有显著意义(除34与36周三者比较P＞0.05外),但至42周时,IGF-1、CP开始下降,IGFBP-1上升,与40周相比,P＜0.05.IGF-1、CP均与胎龄呈中度正相关,而IGFBP-1与胎龄呈高度负相关.结论IGF-1、CP能促进孕晚期胎儿宫内生长,而IGFBP-1则对胎儿生长起抑制作用.因此,营养物质-胰岛素-胰岛素样生长因子系统代谢轴是孕后期调节胎儿生长的重要系统.     

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目的探讨单纯性肥胖儿童的生长与其血清胰岛素(Ins)、胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)浓度的关系。方法2004-03中山大学附属二院对31例单纯性肥胖儿童及48例同龄正常儿童的生长参数及空腹Ins、IGF-1、IGFBP-3浓度进行测定,并进行比较及相关性分析。结果肥胖组血清Ins、IGFBP-3浓度显著高于对照组(P<0·05,P<0·01),而两组间IGF-1差异则无显著性意义,血清Ins浓度与BMI、IGFBP-3呈正相关,肥胖儿童身高SDS与1NS、IGF-1正相关。结论肥胖儿童存在有非生长激素(GH)依赖性生长的代偿机制。其中高胰岛素血症可能参与了这一过程,它既可以通过增加IGFBP-3的合成来间接提高IGF-1的生物活性,又可以直接发挥促生长作用。     

生长激素缺乏症患儿血清胰岛素样生长因子-1及其结合蛋白的变化

目的 研究血清胰岛素样生长因子1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)浓度与生长激素缺乏症(GHD)患儿生长激素(GH)激发试验中血清GH峰值关系,为其代替GH激发试验提供依据。方法选择GHD患儿62例(男39例,女23例),为GHD组;60例健康儿童(男38例,女22例)为对照组。分别用放射免疫分析法(RIA)、免疫放射分析法(IRMA)检测两组血清IGF-1、IGFBP-3浓度,同时做GH激发试验,测定血清GH峰值,并比较其与IGF-1、IGFBP-3的关系。结果 GHD血清IGF-1、IGFBP-3均显著低于对照组(t=3.116、11.579 P均<0.01);GHD组血清IGF-1、IGFBP-3浓度与GH激发试验中GH峰值呈显著正相关(r=0.331、0.347 P均<0.01);GHD组血清IGF-1、IGFBP-3降低阳性率分别为97.58％、98.38％,与激发试验的阳性率(100％)比较无统计学意义(x~2=3.074、2.033 P均>0.05)。结论 血清IGF-1、IGFBP-3浓度的检测对诊断GHD有重要意义;检测血清IGF-1、IGFBP-3浓度可替代GH激发试验。     

The effect of corrective surgery on serum IGF-1, IGFBP-3 levels and growth in children with congenital heart disease

The aim of this study is to evaluate growth and insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels in infants with congenital heart disease (CHD) pre- and postoperatively over a period of a year. Anthropometric values and serum levels of IGF-1 and IGFBP-3 of 40 infants with CHD (20 cyanotic and 20 acyanotic) were compared with 32 healthy controls. Acyanotic infants and infants with pulmonary hypertension (PH) presented significantly more growth failure. Preoperatively, serum IGF-1 and IGFBP-3 levels were lower in the acyanotic group than the cyanotic and the control groups (p = 0.22; p < 0.01). The upward trend in IGF-1 and IGFBP-3 levels in this year-long study demonstrated that the values in the third month and the first year were higher than the preoperative values (p < 0.05). The parallel increase of weight gain and IGF-1, IGFBP-3 levels were the best evidence that these parameters are good nutritional indicators. Timing the corrective surgery before chronic malnutrition or PH develops is an important issue to maintain a normal growth for children with CHD.     

Pharmacokinetics and pharmacodynamics of recombinant human growth hormone by subcutaneous jet- or needle-injection in patients with growth hormone deficiency

Eighteen growth hormone (GH) deficient children and adolescents (11 6/12–20 9/12 y) participated in a randomized open, two-period (4 weeks) cross-over study to evaluate the pharmacokinetics and pharmacodynamics of recombinant human growth hormone (rhGH) administered daily, either by subcutaneous jet-injection or conventional needle-injection. Plasma growth hormone (GH), insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), glucose, insulin, HbAlc and serum-free fatty acids (FFA) levels were analysed repeatedly. GH absorption characteristics, expressed as AUC_0-x, Cmax and Tmax ratio (%) jet-injected over needle-injected were similar in both groups. IGF-I and IGFBP-3 plasma levels were identical in both groups. Serum FFA concentrations were comparable after GH administration with either injection device. Surprisingly nocturnal blood glucose decreased to asymptomatic hypoglycaemic levels in all patients. The results of this study showed equal responses concerning absorption and bioavailability of growth hormone administered daily for 4 weeks by either a jet or a needle-injection device in GH-deficient children and adolescents.     

一个Laron 综合征家系患者临床特点和生长激素受体基因突变分析

Laron 综合征是一种常染色体隐性遗传病,生长激素受体（GHR）基因缺陷是导致Laron 综合征的主要病因。Laron 综合征主要临床特征为生后严重的生长落后伴特殊面容,血生化特点为高生长激素(GH)、低胰岛素样生长因子- (IGF-I) 和低胰岛素样生长因子结合蛋白- (IGFBP-3)。该研究报道一家系2例Laron 综合征患者的临床特点及GHR基因突变。这两个病人为同胞姐弟。弟弟8岁,身高80.0 cm (-8.2 SDS),姐姐11岁,身高96.6 cm (-6.8 SDS)。他们出生体重和身长无特殊,自生后出现生长落后,身高明显落后于同龄正常儿童,并均呈现了典型Laron 综合征外貌特征：身材矮、肥胖、前额突出、大眼睛、塌鼻梁、头发稀软。这两个病人空腹血清GH值均明显高于正常儿童,空腹血清IGF-I明显低于同年龄同性别正常儿童,血浆IGFBP-3和生长激素结合蛋白（GHBP）低于检测线。其中1例（8岁男孩）胰岛素和可乐定刺激后GH峰值大于350 ng/mL,给予重组人生长激素治疗1年,身高由治疗前的80.0 cm 增加至83.3 cm。GHR基因序列测定结果显示2例患者均存在外显子4上第65位氨基酸的纯合突变S65H(TCA → CCA),为新发现的突变。Laron 综合征患者存在特殊的面貌特征,结合血GH、IGF-I、IGFBP-3和GHBP测定可以明确诊断。GHR基因外显子4上S65H突变可能是这两位Laron 综合征患者的致病原因。［中国当代儿科杂志,2007,9（4）：335-338］     

Arm span, serum IGF-1 and IGFBP-3 levels as screening parameters for the diagnosis of growth hormone deficiency in patients with myelomeningocele – preliminary data

Short stature is a common problem in patients with myelomeningocele (MMC) and hydrocephalus. We evaluated auxological and laboratory parameters to differentiate short stature due to neurological defect from short stature additionally caused by growth hormone deficiency (GHD). In a group of 38 prepubertal patients with MMC and hydrocephalus aged 3.8–11.0 years, auxological parameters, including arm span and bone age, and serum insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) levels were measured. Patients with normal supine length (n = 15) had normal arm span. Serum IGF-1 and IGFBP-3 levels were normal (≥ 10th percentile) in 14/15 patients. Twenty-three MMC patients had short stature (height SDS < −2), 11/23 patients had reduced arm span (SDS < −2), and 12/23 had normal arm span. Serum IGF-1 and IGFBP-3 levels were normal in 10/12 of short statured patients with normal arm span, but low (<10th percentile) in those patients with reduced arm span (IGF-1: 8/11 patients, P<0.05; IGFBP-3: 9/11 patients, P<0.005). In 7/11 short statured MMC patients with reduced arm span and low serum IGF-1 and IGFBP-3 levels, growth hormone secretion was investigated. All had a disturbed growth hormone secretion (GHD: n = 4; neurosecretory dysfunction: n = 3). Conclusion Arm span, serum IGF-1 and IGFBP-3 levels are estimated to be appropriate screening parameters for GHD in patients with MMC. Initiating growth hormone therapy should be considered not only according to endocrine findings but also with respect to neurological and orthopaedic anomalies. Received: 27 March 1997 / Accepted: revised form 18 September 1997     

Is there heterozygote expression of growth hormone receptor deficiency?

Expression of heterozygosity for the defect in the growth hormone (GH) receptor has been proposed to be reflected in stature, and in GH binding protein (GHBP) and insulin-like growth factor I (IGF-I) levels in parents and other relatives of patients with GH receptor deficiency (GHRD; Laron syndrome). The Ecuadorean population with GHRD, in which heterozygosity can be accurately determined in clinically unaffected relatives of probands, offers a unique opportunity to consider this issue. It has previously been demonstrated that 17 parents heterozygous for the Ecuadorean mutation of the GH receptor differed little in biochemical measures (GHBP, IGF-I, IGF-II, IGFBP-2 and IGFBP-3) from Ecuadorean controls. Mean height SDS of 24 non-carrier siblings (−1.3 ± 0.95 SD) and 41 heterozygote siblings or offspring of probands (−1.8 ± 1.15) did not differ significantly ( p = 0.08). Thus, although there may be slight heterozygote expression of the defective gene for the GH receptor, there is no rationale for counselling based on such minimal variation.     

肠道炎症阻滞儿童体格生长的免疫和内分泌机制

肠道炎症常伴发儿童的生长落后。生长激素(GH)和胰岛素生长因子-1(IGF-1)是调控出生后骨骼纵向生长的重要物质,抑制GH/IGF轴可阻滞儿童体格生长。肠道发生炎症时,异常升高的促炎症因子IL-1β、IL-6和TNF-α通过干扰GH/IGF轴,系统性以及在生长板局部水平影响骨骼生长,进而导致儿童生长阻滞。     

孤独症谱系障碍儿童的血清胰岛素样生长因子-1和胰岛素样生长因子结合蛋白-3水平研究北大核心CSCD

目的探讨孤独症谱系障碍(autism spectrum disorder,ASD)儿童的血清胰岛素样生长因子-1(insulin-like growth factor-1,IGF-1)和胰岛素样生长因子结合蛋白-3(insulin-like growth factor binding protein-3,IGFBP-3)水平及与孤独症核心症状之间的关系。方法前瞻性选取重庆市妇幼保健院门诊招募的150名2~7岁ASD儿童和165名年龄、性别相匹配的正常健康儿童为研究对象,采用孤独症行为量表和孤独症评定量表评估ASD儿童核心症状,采用化学发光法检测两组儿童血清IGF-1和IGFBP-3水平。结果ASD组儿童血清IGF-1水平低于对照组儿童(P<0.05)。重度ASD儿童血清IGF-1和IGFBP-3水平低于轻-中度ASD儿童(P<0.001),2~3岁ASD儿童血清IGF-1水平低于对照组儿童(P<0.05)。两组男童IGF-1水平均低于女童(P<0.05)。血清IGF-1、IGFBP-3水平与儿童孤独症评定量表总分呈负相关(分别r=-0.32、-0.40,均P<0.001)。结论儿童早期血清IGF-1降低可能与ASD疾病发展相关,血清IGF-1和IGFBP-3水平与ASD儿童核心症状具有一定关联。     

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目的探讨血清生长激素(GH)、胰岛素样生长因子-1(IGF-1)及尿GH检测对矮小儿童诊断的意义。方法华中科技大学同济医院儿科于2004-11—2005-06对106例矮小儿童进行垂体功能复合刺激试验,试验前收集所有受试者夜间12h(2000~800)尿。另选取19例正常青春发育期前儿童为对照组。对垂体功能复合刺激试验GH分泌异常的56例矮小儿童,用ELISA方法检测相应的血清GH、IGF-1及尿中GH水平,并进行相关分析。结果根据垂体功能复合刺激试验的GH检测结果将矮小儿分类,包括完全性GH缺乏症(cGHD)25例、部分性GH缺乏症(pGHD)9例和GH神经分泌功能障碍(GHND)22例。GHD组患儿血清IGF-1、尿GH水平与正常儿相比明显降低(P<0·01)。pGHD和GHND组患儿血IGF-1水平波动较大,无统计学差异。GHND组患儿尿GH水平按ng/g肌酐(Cr)计量显著低于正常对照相(P<0·05),而按ng/12h尿量计算值虽低于正常组,但无统计学意义(P>0·05)。pGHD组患儿尿GH水平按两种方法计量值均介于正常和GHD患者之间,与正常及GHD患者比较均有显著性差异(P均<0·05)。cGHD和pGHD组患儿尿GH的ng/gCr计量值与其血GH峰值呈显著性正相关(rcGHD=0·556,P<0·05;rpGHD=0·423,P<0·05),GHND组患儿尿GH的ng/gCr计量值与其血中GH峰值无相关性(P>0·05)。结论尿GH水平测定无创、简便,配合IGF-1等指标的检测,对于矮小儿童的诊断和鉴别诊断具有重要意义。     

Differential impact of simple childhood obesity on the components of the growth hormone-insulin-like growth factor (IGF)-IGF binding proteins axis

Simple childhood obesity is characterized by normal or even accelerated growth in spite of reduced growth hormone (GH) secretion. There are conflicting reports on the effects of obesity upon components of the GH-insulin-like growth factor-I (IGF-I)-IGF binding proteins (IGFBPs) system. In the present study we aimed to determine GH, IGF-I, IGFBP-3 and IGFBP-2 as well as some of the less explored components of this axis (IGFBP-3 proteolytic activity, IGFBP-3 plasma fragments, and total acid labile subunit [ALS]) in 22 obese and 17 age-matched control children. We also evaluated not only total GH binding protein (GHBP) serum levels but also GHBP bound to GH (complexed) in both groups. Obese and control groups strongly differed in BMI (obese: 4.7 +/- 0.36 vs control: 0.37 +/- 0.25 SDS, p <0.0001). In the obese group, we found lower GH serum levels, but normal serum levels of GH-GHBP complex, IGF-I, IGFBP-3, IGF-I/IGFBP-3 molar ratio, IGFBP-3 proteolytic activity, IGFBP-3 plasma fragments and total ALS. Obese children presented higher total circulating GHBP (6.0 +/- 0.44 vs 2.9 +/- 0.29 nmol/l, p <0.001) and insulin levels (10.5 +/- 1.5 vs 5.1 +/- 0.8 mU/l, p <0.001), while IGFBP-2 (4.6 +/- 0.5 vs 6.6 +/- 0.7%, p <0.05) and the ratio IGFBP-2/IGF-I (0.032 +/- 0.019 vs 0.095 +/- 0.01, p = 0.013) were lower than in controls. BMI and insulin were directly, and IGFBP-2 serum levels inversely, correlated to total GHBP serum levels when multiple regression analysis was performed (r = 0.74, p <0.001). By stepwise regression analysis, insulin (r = -0.37, p <0.05) and BMI (r = -0.52, p <0.01) inversely determined IGFBP-2. In summary, obese children present normal growth in spite of reduced GH secretion, probably because the combination of increased total GHBP and normal GH-GHBP complex serum levels (suggesting increased GH receptor [GHR] number and a normal serum GH reservoir, respectively) allow for the achievement of normal levels of IGF-I, IGFBP-3, IGFBP-3 proteolytic activity, IGFBP-3 plasma fragments and total ALS. Reduced IGFBP-2 serum levels and a lower ratio of IGFBP-2/IGF-I in obese children may suggest an increase of tissue IGF-I bioavailability, thus promoting its action. Normal IGF-I and GH availability may be contributing to maintain normal growth in obese children.