In women with PCOS, serum HMGB1 was measured both at baseline conditions and during the final steady state period of the hyperinsulinemic euglycemic clamp studies, i.e. after about 2 h of exposure to increased insulin levels (mean insulin concentration in the steady state period: 209 ± 52 mU/L). This evidence concerns the gene HMGB1 and polycystic ovary syndrome.