胰岛素样生长因子Ⅰ对儿童青春发育启动的作用

Effect of insulin-like growth factor-Ⅰ on initiation of puberty in children

目的探讨胰岛素样生长因子Ⅰ(IGFⅠ)对正常儿童青春发育启动的可能作用。方法对北方大庆地区526名(男266,女260)健康的6～16岁小学和中学生进行4年的连续观察和研究。每年由相同的内分泌科医师进行体检,检查第二性征的发育,并按Tanner分期法行青春发育分期。同时采血用放射免疫测定或酶联免疫分析法测定血清LH、IGFⅠ和IGF结合蛋白3(IGFBP3)的水平。按年龄和青春发育分期分析血清LH和IGFⅠ、IGFBP3在青春发育过程中的变化及其关系。结果在儿童期不论是男孩还是女孩,随着年龄的增长,血清LH和IGFⅠ、IGFBP3水平有相似的升高趋势。男孩和女孩血清LH水平与IGFⅠ和IGFBP3水平都明显相关(均P<0.01)。血清IGFⅠ水平的开始明显升高在8岁,而LH水平的明显升高在10岁,表明血清IGFⅠ水平的升高要比LH升高早2年。以青春发育期进行分析,女孩在青春发育2期血清IGFⅠ水平明显高于1期,也早于LH水平升高(3期)。男孩则显示血清LH、IGFⅠ和IGFBP3水平在2期同时升高。结论儿童期循环中血清IGFⅠ水平的升高早于LH水平的升高,提示IGFⅠ可能是调节儿童青春发育启动的外周因素之一。

Objective To investigate the possible role of insulin-like growth factor-Ⅰ（IGF-Ⅰ） in the initiation of puberty in children. Methods A total of 526 healthy students （ boy 266, girl 260） aged 6-16 years from primary and middle schools in Daqing area of Northern China accepted developmental examination of secondary sexual characteristics including breast, external genitalia and pubic hair, and determination of serum levels of LH, IGF-Ⅰ and IGF binding protein-3 （IGFBP-3） by radio immunoassay or ELISA and were consecutively followed up for 4 years. Results The developmental changes in the serum levels of IGF-Ⅰ , IGFBP-3 and LH showed similar increasing patterns in the children and adolescents of both boys and girls. The relationships between the serum concentrations of LH and IGF-Ⅰ or IGFBP-3 were very significant in boys and girls （all P〈0.01 ）. In an age-related analysis, the serum level of IGF-Ⅰ began significant increase at 8 years old, being 2 years earlier than that of LH in both boys and girls. In a pubertal stage-related analysis, the serum level of IGF-Ⅰ in girls showed significant rise during Tanner stage 2, while the increase of LH level occurred during Tanner stage 3. In boys, the serum levels of IGF-Ⅰ and LH increased significantly during the same Tanner stage 2. Conclusions The elevated level of circulating IGF-Ⅰ occurred earlier than that of LH level in children, indicating that IGF-Ⅰ seems to be one of the factors for the initiation of puberty.