Free and bound leptin in prepubertal children with Down's syndrome and different degrees of adiposity.
OBJECTIVE
To evaluate plasma total, free (FL) and protein-bound (BL) leptin in children with Down's syndrome (DS) and different degrees of adiposity and its relationship with thyroid stimulating hormone (TSH), free thyroxine (FT(4)), and free triiodothyronine (FT(3)).


METHODS
A total of 24 prepubertal clinically euthyroid DS children.


METHODS
Plasma leptin, TSH, FT(4), and FT(3) concentrations were determined by immunometric/radioimmunologic assays. FL and BL were evaluated by fast protein liquid chromatography.


RESULTS
In DS children, leptin circulates in two fractions, corresponding to BL and FL. The amount of BL and FL is negatively and positively correlated to body mass index (BMI), respectively. Plasma leptin concentrations correlate with BMI, but not with TSH, FT(4), and FT(3).


CONCLUSIONS
In prepubertal DS children, leptin circulates as both BL and FL, correlates with adiposity and its concentration appears independent of thyroid function.
Magni
P
P
Department of Endocrinology, Centre of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy. paolo.magni@unimi.it
Ruscica
M
M
Dozio
E
E
Roti
E
E
Licastro
F
F
Motta
M
M
Corsi
M M
MM
D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000097:blood*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D020738:Leptin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine