Retinol-binding protein 4 in polycystic ovary syndrome--association with steroid hormones and response to pioglitazone treatment.
BACKGROUND
Polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance.


OBJECTIVE
The aim of the study was to investigate a putative role of the adipokines retinol-binding protein 4 (RBP4), adiponectin, and visfatin in a cohort of patients with PCOS and their response to treatment with pioglitazone.


METHODS
We conducted a randomized, controlled, double-blind study at a tertiary referral center.


METHODS
Forty premenopausal women with PCOS were allocated to receive treatment with either pioglitazone (30 mg/d) or a placebo for a period of 3 months.


METHODS
Serum concentrations of RBP4, adiponectin, and visfatin were determined along with metabolic and hormonal parameters before and after treatment.


RESULTS
Serum adiponectin concentrations were higher after treatment with pioglitazone (P = 0.003), whereas RBP4 levels tended to decrease (P = 0.06), and visfatin concentrations remained unchanged. We found RBP4 serum concentrations at baseline to be positively correlated with serum levels of testosterone (R = 0.446; P = 0.005), 17-OH progesterone (R = 0.345, P = 0.037), and dehydroepiandrosterone sulfate (R = 0.347; P = 0.041). However, these correlations were abolished after treatment with pioglitazone. Patients with high RBP4 levels had significantly higher hirsutism scores (P = 0.038 before and P = 0.034 after treatment). In contrast, serum adiponectin concentrations were related to parameters of impaired glucose metabolism, and no significant associations were detected for visfatin.


CONCLUSIONS
Our results suggest that RBP4 may contribute to endocrine changes and to the phenotypic manifestation of patients with PCOS because higher RBP4 concentrations are associated with higher androgen levels and higher clinical hirsutism scores independently of pioglitazone treatment. The molecular involvement of RBP4 in human steroid metabolism requires further clarification.
Aigner
Elmar
E
Department of Internal Medicine, General Hospital Oberndorf/Salzburg, Oberndorf, Austria.
Bachofner
Nora
N
Klein
Kerstin
K
De Geyter
Christian
C
Hohla
Florian
F
Patsch
Wolfgang
W
Datz
Christian
C
D054392:Adipokines / Q000097:blood; D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D004311:Double-Blind Method; D005260:Female; D006628:Hirsutism / Q000097:blood / Q000453:epidemiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood; D000077205:Pioglitazone; D010919:Placebos; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000188:drug therapy*; D017697:Premenopause; D054839:Retinol-Binding Proteins, Plasma / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000097:blood; D045162:Thiazolidinediones / Q000627:therapeutic use*
D054392:Adipokines; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D010919:Placebos; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma; D045162:Thiazolidinediones; D013739:Testosterone; D000077205:Pioglitazone