Free and total leptin serum levels and soluble leptin receptors levels in two models of genetic obesity: the Prader-Willi and the Down syndromes.
Alterations in energy balance and feeding behavior and the subsequent high frequency of obesity are hallmarks of 2 chromosomal diseases: the Prader-Willi syndrome (PWS) and the Down syndrome (DS). Leptin, an important regulator of food intake and energy homeostasis, circulates in 2 forms: a free, therefore active, fraction and a fraction bound to the soluble leptin receptor, whose bioavailability consequently participates in the regulation of leptin action. To investigate the possible role of the free-bound leptin balance in the pathogenesis of obesity in PWS and DS, we enrolled 7 obese women with DS, 5 obese women with PWS, 7 obese women, and 7 normal-weight healthy control women. Basal hormonal concentrations, total and free leptin levels, and leptin receptors levels were measured in plasma samples obtained from the 4 groups. No significant differences were observed in the hormonal milieu. Women with DS exhibited lower total leptin concentrations (P<.01), comparable leptin receptor level and, therefore, lower free leptin values (P<.01) when compared with obese controls, then resembling the profile peculiar to normal-weight control women. At variance, subjects with PWS did not differ from obese controls regarding both leptin and leptin receptor levels. Our data suggest that, whereas subjects with PWS have a leptin assessment corresponding to their degree of obesity, subjects with DS may have a defect in the secretion of leptin that could at least partially account for this form of syndromal obesity.
Proto
Caterina
C
Laboratories Department, Oasi Institute for Research Maria SS, 94018 Troina (EN), Italy.
Romualdi
Daniela
D
Cento
Rosa Maria
RM
Romano
Corrado
C
Campagna
Giuseppe
G
Lanzone
Antonio
A
D000328:Adult; D004314:Down Syndrome / Q000097:blood* / Q000150:complications / Q000235:genetics*; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D020738:Leptin / Q000097:blood*; D009765:Obesity / Q000097:blood* / Q000209:etiology / Q000235:genetics*; D011218:Prader-Willi Syndrome / Q000097:blood* / Q000150:complications / Q000235:genetics*; D011863:Radioimmunoassay; D011956:Receptors, Cell Surface / Q000097:blood*; D054411:Receptors, Leptin
D006728:Hormones; C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin