Retinol-binding protein 4 in adipose and placental tissue of women with gestational diabetes.

In the present study, we evaluated serum levels of retinol-binding protein 4 (RBP4) and the expression of RBP4, glucose transporter-4 (GLUT4) and peroxisome proliferator activated receptor gamma (PPARγ) mRNA (using quantitative real time-PCR) in subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and placental tissue obtained from patients with gestational diabetes (GDM) and healthy pregnant women. Serum RBP4 concentrations and its expression in SAT were higher in the women with GDM than in the controls (p = 0.03). No association between serum or tissue RBP4 and the indices of insulin resistance was noted. In the GDM group serum RBP4 correlated with its mRNA expression in SAT (r = 0.67, p = 0.007). Stepwise regression analysis revealed that RBP4 mRNA expression in SAT was independently predicted by GLUT4 mRNA expression (β= 0.59, p = 0.003) and the presence of GDM (β=0.46, p = 0.01), whereas RBP4 mRNA expression in VAT was related to PPARγ mRNA expression (β= 0.64, p = 0.0003) and the patient's age (β= -0.38, p = 0.03). In conclusion, our results suggest that the elevated expression of RBP4 in SAT may contribute to the increase in circulating RBP4 in GDM subjects.