Preliminary data on effects of metformin on PED/PEA-15 cellular levels in obese women with polycystic ovary syndrome

Background: The cellular abundance of the phosphoprotein enriched in diabetes (PED/PEA-15), a 15 kDa protein related to insulin resistance (IR), is increased in women with polycystic ovary syndrome (PCOS). Aim: To investigate whether metformin (MET) has additive effects on PED/PEA-15 protein levels. Material/subjects and methods: This is an open label, prospective clinical study over 6 months. Ten hyperandrogenic obese PCOS women [age: 24.6±1.6 yr; body mass index (BMI): 30.7±1.2 kg/m2] were treated with MET (1250 mg/day). Ten age- and BMI-matched normo-androgenic women were used as controls. Outcome measures are: PED/PEA-15 protein levels, fasting plasma glucose and insulin (FPI), reciprocal index of homeostasis model assessment of insulin resistance (1/HOMA-IR); quantitative insulin sensitivity check index (QUICKI); whole-body insulin sensitivity index (ISI); SHBG; total testosterone; free androgen index (FAI). Results: At baseline FPI and PED/PEA-15 protein levels were higher, while 1/HOMA-IR, QUICKI, and ISI were lower (p<0.001) in MET group than in controls. After treatment, independently of body weight and hyperandrogenism, FPI, and PED/PEA-15 protein levels decreased (p=0.001 and 0.004, respectively), while, 1/HOMA-IR, QUICKI, and ISI increased (p<0.001). PED/PEA-15 protein levels correlated significantly with ISI either before (r=0.636; p=0.048), and after treatment (r=0.758; p=0.011). Conclusions: PED/PEA-15 protein levels reduced after a short course of treatment with MET in a group hyperandrogenic obese PCOS women. This effect was independent of body weight and hyperandrogenism, and correlated with ISI, thus adding a further benefit to obese PCOS women.