Serum Leptin Levels in Children according to Pubertal Stage

Park, Sang Hyon; Lee, Kee Hyoung; Lee, Jung Hwa; Shin, Young Kyoo; Eun, Baik Lin; Kim, Soon Kyum

Abstract

PURPOSE: Leptin is a hormone, encoded by ob gene in adipocytes and regulates food intake and energy expenditure. The serum concentration of leptin is known to be proportional to the amount of body fat but the regulation of leptin for growth and development in childhood is not clear. The purpose of this study is to evaluate the correlation of serum leptin levels to gender, pubertal development and sex steroid in children.
METHODS
Serum leptin levels were measured by RIA in 145 Korean children of both sexes, age 8-16yr, and were compared according to body mass index, gender and pubertal stage. The correlations of leptin with testosterone and estradiol were also analized.
RESULTS
A positive relationship was observed for leptin levels with body mass index(in male:r=0.63, P<0.001, in female:r=0.80, P<0.001). The mean leptin level of girls was higher than that of boys(7.50+/-.83ng/mL vs 4.11+/-.72ng/mL, P<0.05) in lean children but there was no significant difference in obese group. An analysis according to the pubertal development showed an increase of leptin level in girls while leptin decreased in boys at overt puberty. Serum leptin levels of boys in puberty correlated inversely with testosterone(r=-0.52, P<0.001) but leptin of girls did not have significant correlation with estradiol.
CONCLUSION
Serum leptin level increases in girls and decreases in boys as the pubertal development proceeds. The relationships between leptin level and pubertal developement show gender difference and it might be explained in part by suppressive effects of androgen in male.