The oral glucose tolerance test (OGTT) consisted of 75 g of glucose administered orally after three days of a carbohydrate-rich diet; blood samples for glucose and insulin measurements were drawn before administration of the glucose solution and 30, 60, 90, and 120 min after administration.
Plasma glucose concentration was determined using the glucose oxidase method [24 (link)]. All lipid measurements were obtained directly from plasma samples. The total cholesterol and triglyceride levels were assessed using enzymatic methods (Roche Laboratories). HDL-C was quantified using the same method, and LDL-C was estimated using the Friedwald formula [25 (link)]. Glycated hemoglobin was measured using high-performance liquid chromatography [25 (link)] in a centrifuge. Progesterone was measured using an immunofluorometric assay (Wallac, Helsinki, Finland) using Auto DELFIA kits; androstenedione, prolactin (PRL), luteinizing hormone (LH), and follicular stimulating hormone (FSH), by the immunofluorometric assay; dehydroepiandrosterone sulfate (DHEAS), by radioimmunoassay (Cisbio International, Saclay, France, and DSL, Houston, TX, USA); insulin and 17-OHP, by radioimmunoassay using DSL kits. Testosterone and sex hormone-binding globulin (SHBG) levels were measured using an electrochemiluminescent immunoassay (Modular; Roche). The free testosterone index was calculated using the following formula: total testosterone/SHBG × 100. Free testosterone levels were calculated using the Vermeulen formula. All analyses were performed twice, and the intra- and inter-assay coefficients of variation did not exceed 10% and 15%, respectively.
Plasma glucose concentration was determined using the glucose oxidase method [24 (link)]. All lipid measurements were obtained directly from plasma samples. The total cholesterol and triglyceride levels were assessed using enzymatic methods (Roche Laboratories). HDL-C was quantified using the same method, and LDL-C was estimated using the Friedwald formula [25 (link)]. Glycated hemoglobin was measured using high-performance liquid chromatography [25 (link)] in a centrifuge. Progesterone was measured using an immunofluorometric assay (Wallac, Helsinki, Finland) using Auto DELFIA kits; androstenedione, prolactin (PRL), luteinizing hormone (LH), and follicular stimulating hormone (FSH), by the immunofluorometric assay; dehydroepiandrosterone sulfate (DHEAS), by radioimmunoassay (Cisbio International, Saclay, France, and DSL, Houston, TX, USA); insulin and 17-OHP, by radioimmunoassay using DSL kits. Testosterone and sex hormone-binding globulin (SHBG) levels were measured using an electrochemiluminescent immunoassay (Modular; Roche). The free testosterone index was calculated using the following formula: total testosterone/SHBG × 100. Free testosterone levels were calculated using the Vermeulen formula. All analyses were performed twice, and the intra- and inter-assay coefficients of variation did not exceed 10% and 15%, respectively.
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