Decreased soluble leptin receptor levels in women with polycystic ovary syndrome.
OBJECTIVE
Polycystic ovary syndrome (PCOS) is associated with insulin resistance and a high incidence of obesity. Leptin, the product of the ob gene, is involved in the regulation of energy balance and obesity and circulates in both free and bound forms. The soluble leptin receptor (sOB-R) is the most important leptin-binding protein, thus influencing the biologically active free leptin level.


METHODS
We assessed the correlation of metabolic and endocrine parameters with leptin and sOB-R levels in 122 PCOS women (aged 27 +/- 5.7 years) and 81 healthy controls (aged 25 +/- 4.0 years).


METHODS
Leptin and sOB-R levels were measured using ELISA kits. In addition, anthropometric variables, body fat and endocrine parameters were evaluated and a glucose tolerance test performed to assess indices of insulin resistance and glucose metabolism.


RESULTS
In PCOS patients, no correlation was found between leptin or sOB-R and parameters of hyper-androgenism. However, as expected, body mass index (BMI), body fat, waist circumference and indices of insulin resistance were significantly correlated with leptin in PCOS subjects and controls. In a subgroup analysis of lean, overweight and obese PCOS patients, significant differences were found in leptin (29.7 +/- 20.7 vs 45.4 +/- 25.0 vs 67.7 +/- 28.8 ng/ml, P < 0.0001) and sOB-R (8.0 +/- 3.4 vs 6.4 +/- 2.5 vs 5.7 +/- 2.3 ng/ml, P < 0.05). Compared with BMI-matched controls, lean PCOS patients had lower sOB-R levels (8.0 +/- 3.4 vs 12.7 +/- 4.7 ng/ml, P < 0.0001) and higher free leptin indices (4.5 +/- 3.9 vs 2.8 +/- 2.2, P = 0.0285).


CONCLUSIONS
Taking into account that low sOB-R levels supposedly compensate diminished leptin action, PCOS per se might cause leptin resistance.
Hahn
Susanne
S
Division of Endocrinology, Department of Medicine, University of Duisburg-Essen, Essen, Germany.
Haselhorst
Uwe
U
Quadbeck
Beate
B
Tan
Susanne
S
Kimmig
Rainer
R
Mann
Klaus
K
Janssen
Onno E
OE
D000328:Adult; D000735:Androstenedione / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood / Q000378:metabolism; D009765:Obesity / Q000378:metabolism; D011085:Polycystic Ovary Syndrome / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000097:blood / Q000378:metabolism*; D054411:Receptors, Leptin; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D018709:Statistics, Nonparametric; D013739:Testosterone / Q000097:blood; D013972:Thyrotropin / Q000097:blood
D001786:Blood Glucose; C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D000735:Androstenedione; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D002784:Cholesterol; D006854:Hydrocortisone