Assessments
BLOOD, INSULIN RESISTANCE
Height and weight were measured and BMI calculated. Blood samples were obtained-in the follicular phase or after 2 months of amenorrhea- in the morning after an overnight fast. Serum glucose was measured by the glucose oxidase method. Insulin, testosterone and sex hormone binding globulin (SHBG) were assayed by immunochemiluminiscence (DPC IMMULITE 2500, Siemens, Erlangen, Germany); intra- and inter-assay coefficients of variation (CVs) were <10%; HDL-cholesterol, LDL-cholesterol and triglycerides were assessed by an enzymatic method and C-reactive protein (CRP) was measured with a hightly sensitive method (Architect c8000 autoanalyzer, Abbott laboratories, North Chicago, IL). Homeostasis model assessment for insulin resistance (HOMA-IR) was calculated as fasting insulin (mU/L) x fasting glucose (mmol/L)/22.5.Circulating follistatin and HMW-adiponectin were measured by specific ELISAs (R&D Systems, Minneapolis, USA) with intra- and inter-assay CVs <9% for both assays.Abdominal fat partitioning (subcutaneous and visceral fat areas) as well as liver fat were assessed by magnetic resonance imaging (MRI) using a multiple-slice MRI 1.5 Tesla scan (Signa LX Echo Speed Plus Excite, General Electric, Milwaukee, WI), as reported (