Metabolism: clinical and experimental
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In normal subjects, the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are responsible for 70% of the insulin response during a meal; but in diabetic subjects and other insulin-resistant conditions, the incretin effect is impaired. Polycystic ovary syndrome (PCOS) is associated with insulin resistance, and the pathophysiologic mechanisms behind PCOS resemble those of type 2 diabetes mellitus; therefore, women with PCOS may have alterations in the incretin hormone response. Metformin is widely used in the treatment of both type 2 diabetes mellitus and PCOS. ⋯ Subgroup analysis showed lower GIP (area under the curve [AUC]) levels in obese women with PCOS compared with obese control women (P < .05) and compared with lean women with PCOS (P < .05). Metformin increased GIP (AUC) and GLP-1 (AUC) in lean women with PCOS (P < .05), and a similar trend was seen in the obese women (P = .07). The GIP secretion is attenuated in obese women with PCOS, whereas treatment with metformin increases the levels of both GIP and GLP-1 in women with PCOS.