Potential effect of adrenomedullin on metabolic and endocrinal dysfunctions in the experimentally induced polycystic ovary: Targeting implication of endoplasmic reticulum stress

This study investigated the potential effect of adrenomedullin (ADM) on metabolic and endocrinal dysfunctions in experimentally induced polycystic ovary. Twenty‐four female Wistar rats were allocated into three groups: control; polycystic ovary syndrome (PCOS) in which PCOS was induced by letrozole, orally in a dose of 1 mg/kg once daily for 3 weeks; and ADM group in which ADM was injected intraperitonally in a dose of 3.5/μg/twice daily for 4 weeks. At the end of the experimental period, the serum sex hormone profile, ADM, fasting glucose, insulin, homeostatic model assessment of insulin resistance, and lipid parameters were determined. Ovarian tissue homogenates were used to determine malondialdehyde, total antioxidant capacity, glutathione peroxidase activity, tumor necrosis factor α, interleukin 6, B cell lymphoma‐2 (Bcl‐2), and Bcl‐2 associated X protein. The profibrotic growth factors, including transforming growth factor β1 and connective tissue growth factor, were determined; and also, the relative gene expression of endoplasmic reticulum (ER) stress, including (Xbox‐binding protein‐1 [XBP‐1], activating transcription factor 6 [ATF6], and homologous protein [CHOP]), serine/threonine kinase 1 (Akt1), phosphatidylinositol 3‐kinase (PI3K), and peroxisome proliferator‐activated receptor γ (PPAR‐γ) were determined. Finally, histopathological analysis of the ovaries was evaluated. PCOS group exhibited increased ER stress, suppressing of PI3K/Akt1 and PPAR‐γ pathways, imbalance of sex hormonal profile, hyperglycemia, insulin resistance, dyslipidemia, increased profibrotic factors, and abnormal ovarian histopathological picture, while ADM treatment alleviated these disturbances occurring in the PCOS model. We concluded that ADM mitigated PCOS via attenuating the ER stress, in addition to activation of PI3K/Akt1 and PPAR‐γ pathways, its antioxidant, anti‐inflammatory, antiapoptotic, and antifibrotic properties. This graph showed that letrozole polycystic ovary syndrome (PCOS) via multiple pathogenesis mechanisms, including hyperandrogenemia, hyperglycemia, hyperinsulinemia, dyslipidemia, and oxidative stress. All these mentioned disturbances led to insulin resistance (IR). Also, letrozole increased the production of proinflammatory cytokines, apoptosis, and stimulated profibrotic factors as transforming growth factor β1 (TGF‐β1) and connective tissue growth factor (CTGF). All these aforementioned disturbances increased endoplasmic reticulum (ER) stress, whi