The relationship between retinol-binding protein 4 levels, insulin resistance, androgen hormones and polycystic ovary syndrome.
BACKGROUND
Retinol-binding protein 4 (RPB4), a 21-kDa peptide, is a recently identified adipokine that may contribute to the pathogenesis of polycystic ovary syndrome (PCOS). The aim of this study was to explore the association between serum RBP4 levels, androgen hormones and insulin resistance (IR) in women with PCOS.


METHODS
In this case-control study, 75 PCOS patients and 53 age- and body mass index (BMI)-matched control subjects referred to the Zanjan Metabolic Disease Research Center were enrolled. Serum RBP4 was measured using an enzyme-linked immunosorbent assay. BMI, waist circumference (WC), fasting levels of glucose, lipid profiles and insulin were also measured. A homeostatic model assessment of insulin resistance (HOMA-IR) value was used to determine the level of insulin resistance.


RESULTS
PCOS cases had significantly higher serum RBP4 and insulin levels than control subjects (44130 ± 12760 vs. 32980 ± 9560 μg/L, p < 0.001, and 11790 ± 11480 vs. 7890 ± 4300 μU/L, p < 0.05, respectively), in univariable analysis. RBP4 showed a positive correlation with serum testosterone (r = 0.62, p < 0.0001), dehydroepiandrosterone sulfate (r = 0.45, p < 0.0001) and the waist circumference (r = 0.37, p < 0.001) of PCOS patients but not with other measured clinical and biochemical variables. However, no correlation was observed between serum RBP4 levels and HOMA-IR in all studied subjects. A final logistic regression analysis demonstrated that testosterone and dehydroepiandrosterone sulfate are independently associated with PCOS.


CONCLUSIONS
These findings indicate that RBP4 is not independently associated with PCOS. The elevation of RBP4 levels in PCOS women might be influenced by androgen hormones. Further prospective studies are needed to clarify molecular mechanisms.
Zanjan Metabolic Disease Research Center, Zanjan University of Medical Sciences, Zanjan, Iran.
Ali Awsat
AA
Mellati
Faranak
F
Sharifi
Mohsen
M
Sajadinejad
Davood
D
Sohrabi
Saeideh
S
Mazloomzadeh
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood; D016015:Logistic Models; D008875:Middle Aged; D011085:Polycystic Ovary Syndrome; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism*; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
D007328:Insulin; D008055:Lipids; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma; D013739:Testosterone; D019314:Dehydroepiandrosterone Sulfate