[Blood leptin, orexins and NPY levels and their relations in obese children].

ABSTRACT

OBJECTIVE: To investigate the concentration levels of leptin, orexins and neuropeptide Y (NPY) in the blood of obese children, and to analysed the relationship between these substances. METHODS: RIA methods were used to measure the concentrations of leptin, orexinA, orexinB, and NPY in the blood of 98 obese children [BMI male (29.24 +/- 1.87) kg/mZ, female (28.12 +/- 2.30) kg/m2] and in 104 normal children [BMI male (20.49 +/- 1.95) kg/m2, female (19.59 +/- 1.51) kg/m2] as the control group. RESULTS: The leptin concentrations in obese children [male (26.00 +/- 14.66) ng/mL; female (33.59 +/- 14.63) ng/mL] were higher than those in the control group [male (6.65 +/- 44.49) ng/mL; female [10.48 +/- 5.52) ng/mL P < 0.013]. The concentrations of plasma orexinA in obes children [male (3.23 +/- 1.86) pg/mL; female (3.38 +/- 1.80) pg/mL] were lower than those in the control group [male (4.52 +/- 1.52) pg/mL; female (4.71 +/- 1.53) pg/mL P < 0.05]; Negative correlations between leptin and NPY were noted in the obesity group (r = -0.302) and the control group (r = -0.310, P < 0.01), while the slopes in the two groups were different (control group -2.969; obese group -0.809). A positive correlation between NPY and orexinA was noted (r = 0.207, P < 0.05). The fluctuation range of orexinA in obese children was markedly narrowed when compared with that in the control group. CONCLUSION: The concentration level of peripheral orexinA and leptin in the obese and non-obese children change inversely. The obesity in children correlates with the concentrations of orexinA, leptin, NPY as well as with their interactions.