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

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.

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.

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.

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.