Serum levels of leptin, adiponectin, retinol binding protein 4 and leptin/adiponectin molar ratio as another possible marker of insulin resistance in obese

Abstract

Aim: To determine the relationship between some adipokines and insulin resistance (IR) in obese.

Materials and methods: 47 individuals were divided--1. according to BMI to subgroups with normal weight, overweight and obesity, 2. according to IR HOMA index to subjects with IR (IR HOMA > 1.88) and subjects without IR. Except the basic biochemical parameters, serum level of fasting insulin, leptin, retinol binding protein 4 (RBP4) (RIA), adiponectin (ELISA) and leptin/adiponectin (L/A) molar ratio were examined.

Results: 1. In correlation to BMI--subjects with BMI > 30 showed significantly higher level of insulin (16.1 +/- 4.1/5.9 +/- 4.1), leptin (51.9 +/- 26.4/14.7 +/- 14) and molar ratio LA (3.1 +/- 1.8/0.48 +/- 0.2) (p < 0.01) and significantly lower level of adiponectin (18.9 +/- 6.3/35.5 +/- 10.5) (p < 0.01) in comparison to both other subgroups (normal weight, overweight). There was no statistically significant difference in RBP4 level between all subgroups, although the highest level of RBP4 was observed in subjects with BMI > 30. In correlation to IR-- subjects with IR showed significantly higher BMI (35.7 +/- 5.8/24.8 +/- 2.6), insulin (15.5 +/- 7.1/4.8 +/- 1.6), leptin (47.2 +/- 29.2/15.1 +/- 13), L/A molar ratio (2.7 +/- 0.3/0.5 +/- 0.1) (p < 0.01), and RBP4 (561.6 +/- 152.5/450.9 +/- 101.7 (p < 0.05) as well. In IR subjects, serum level of adiponectin was significantly lower in comparison to subjects without IR (19.8 +/- 6.3/32.2 +/- 0.8) (p < 0.01).

Conclusion: Decreased level of adiponectin and increased level of leptin, RBP4 and leptin/adiponectin molar ratio in obese can be also considered as a marker of developing insulin resistance (Tab. 2, Ref. 23).