Weight loss increases soluble leptin receptor levels and the soluble receptor bound fraction of leptin.
OBJECTIVE
Soluble leptin receptor (sOB-R) represents the main binding site for leptin in human blood. The aim of this study was to investigate the relationship between leptin and soluble leptin receptor and the bound/free ratio after pronounced weight reduction.


METHODS
A total of 18 morbidly obese women participated in this prospective study. Subjects were examined for fat mass, leptin, and sOB-R concentrations before and 1 year after Swedish adjustable gastric banding.


RESULTS
Anthropomorphic measures displayed a significant reduction of body mass index [(42.9 +/- 5.6 to 32.9 +/- 6.0 kg/m(2) (mean +/- SD)]. Fat mass decreased from 56.3 +/- 9.0 to 33.9 +/- 12.5 kg. Plasma leptin concentration decreased from 44.6 +/- 18.0 to 20.0 +/- 13.1 ng/mL (p < 0.001), whereas the sOB-R levels increased from 11.1 +/- 3.6 to 16.6 +/- 6.0 U/mL after weight-reducing surgery. Thus, the sOB-R bound fraction of leptin increased from 7% to 33%.


CONCLUSIONS
This work demonstrates a relationship between weight loss, leptin, and sOB-R concentrations in vivo. During weight loss, leptin levels decreased, whereas sOB-R levels and the receptor bound fraction of leptin increased. Thus, sOB-R may negatively regulate free leptin.
Laimer
Markus
M
Department of Medicine, University of Innsbruck, Austria.
Ebenbichler
Christoph F
CF
Kaser
Susanne
S
Sandhofer
Anton
A
Weiss
Helmut
H
Nehoda
Hermann
H
Aigner
Franz
F
Patsch
Josef R
JR
D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D015391:Gastroplasty; D006801:Humans; D020738:Leptin / Q000097:blood*; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000601:surgery*; D011446:Prospective Studies; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000097:blood*; D054411:Receptors, Leptin; D012995:Solubility; D015431:Weight Loss
C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin