Estradiol Testosterone Ratio, Serum Retinol Binding Protein 4 and Insulin Resistance in Overweight and Obese Egyptian Men

Overweight and obesity are the leading causes for the development of multiple adverse metabolic effects. Retinol Binding Protein 4 (RBP4), a peptide secreted from adipocytes and hepatocytes, provides a new link between obesity and insulin resistance. The objective of this work is to determine RBP4 serum levels and evaluate its relationship with serum testosterone (T), serum estradiol (E2), E2/T ratio and insulin resistance in overweight and obese Egyptian men. The study included 65 men which were subdivided into (20 normal weight, 20overweight and 25 obese). Their mean age was (43.88±5.52). Serum RBP4 was measured by the enzyme linked immunosorbent assay. Serum RBP4 and E2/T ratio were significantly higher, while serum T was significantly lower in overweight and obese groups as compared with normal weight group. In all subjects, serum RBP4 correlated positively with BMI, waist circumference, waist-to-hip ratio (WHR), HOMA-IR, serum E2 and E2/T ratio. In contrast, it correlated negatively with quantitative insulin sensitivity check index (QUICKI) and serum T. In multiple linear regression analysis serum RBP4 was independently associated with E2/T ratio. It could be concluded that serum RBP4 is elevated in overweight and obese as compared with normal weight subjects, and that the disturbance in E2/T ratio seem to affect RBP4 serum levels and insulin sensitivity in obese men.