The influence of orlistat, metformin and diet on serum levels of insulin-like growth factor-1 in obeses women with and without insulin resistance.

A range of studies showed confusing data about the relationship between obesity, weight reduction and circulating total insulin-like growth factor -1 (IGF-1). The aim of the study was to compare the influence of orlistat (IO), metformin (IM), or calorie-restricted diet (LC) on IGF-1, with special respect to insulin-resistance status. One hundred and fourteen obese women aged from 18 to 40 years were divided into insulin sensitive (IS) and insulin resistant (IR) groups and received a low calorie diet (LC), or an isocaloric diet and 500 mg metformin twice daily (IM), or isocaloric diet with 120 mg orlistat three times daily (IO). Before and after the intervention anthropometric parameters, serum lipid profile, serum concentrations of alanine aminotransferase, aspartate aminotransferase, insulin, glucose, IGF-1, HOMA-IR (homeostatic model assessment), and visceral adiposity index (VAI), and their changes were registered. Although the reductions in weight and body fat were comparable in IS and IR groups, only women with IR showed a significant increase in IGF-1 concentration as a result of all interventions. We found significant positive correlations of ΔIGF-1 with initial and Δ values of: HOMA-IR, triglyceride/high-density cholesterol ratio, VAI. IR premenopausal women show significant increase in IGF-1 serum concentrations regardless the method of intervention. The increase in IGF-1 was parallel to the improvement of insulin resistance parameters.