Associations of Serum GIP, GLP-1, and DPP-4 with Metabolic and Hormonal Profiles and Tobacco Exposure in Women with Polycystic Ovary Syndrome.

Disorders in glucose metabolism are well-established features of polycystic ovary syndrome (PCOS) and are linked to its clinical severity and phenotypic variability. This study aimed to assess serum concentrations of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and dipeptidyl peptidase-4 (DPP-4) and to examine their relationships with glucose and insulin levels, selected sex hormone concentrations, body weight, and exposure to tobacco smoke. Women with PCOS exhibited significantly elevated levels of fasting glucose, insulin, GIP, and GLP-1 compared to controls. Tobacco smoke exposure in women with PCOS was associated with reduced DPP-4 levels, which were approximately two-fold lower in smokers than in non-smokers. A significant negative correlation between DPP-4 and cotinine levels further supported this relationship. Comorbidities such as overweight/obesity or insulin resistance (IR) were also linked to elevated incretin hormone levels. However, no significant age-related trends in incretin levels were identified, despite the known association between age and glucose dysregulation. The notable alterations in incretin hormone profiles in PCOS, along with the consistent patterns of GIP or GLP-1 with metabolic and hormonal parameters, suggest that these hormones may play coordinated regulatory roles in the pathophysiology of PCOS.