Dihydrotestosterone deteriorates cardiac insulin signaling and glucose transport in the rat model of polycystic ovary syndrome

It is supposed that women with polycystic ovary syndrome (PCOS) are prone to develop cardiovascular disease as a consequence of multiple risk factors that are mostly related to the state of insulin resistance and consequent hyperinsulinemia. In the present study, we evaluated insulin signaling and glucose transporters (GLUT) in cardiac cells of dihydrotestosterone (DHT) treated female rats as an animal model of PCOS. Expression of proteins involved in cardiac insulin signaling pathways and glucose transporters, as well as their phosphorylation or intracellular localization were studied by Western blot analysis in DHT-treated and control rats. Treatment with DHT resulted in increased body mass, absolute mass of the heart, elevated plasma insulin concentration, dyslipidemia and insulin resistance. At the molecular level, DHT treatment did not change protein expression of cardiac insulin receptor and insulin receptor substrate 1, while phosphorylation of the substrate at serine 307 was increased. Unexpectedly, although expression of downstream Akt kinase and its phosphorylation at threonine 308 were not altered, phosphoiylation of Akt at serine 473 was increased in the heart of DHT-treated rats. In contrast, expression and phosphorylation of extracellular signal regulated kinases 1/2 were decreased. Plasma membrane contents of GLUT1 and GLUT4 were decreased, as well as the expression of GLUT4 in cardiac cells at the end of androgen treatment. The obtained results provide evidence for alterations in expression and especially in functional characteristics of insulin signaling molecules and glucose transporters in the heart of DHT-treated rats with PCOS, indicating impaired cardiac insulin action. (c) 2014 Elsevier Ltd. All rights reserved.Ministry of Education, Science and Technological Development, Republic of Serbia {[}III41009

Cardiac fatty acid uptake and metabolism in the rat model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with an altered plasma lipid profile and increased risk for cardiovascular diseases. We hypothesized that molecular mechanisms underlying cardiac pathology in PCOS involve changes in expression and subcellular localization of several key proteins involved in cardiac lipid transport and metabolism, such as fatty acid transporter CD36, lipin 1, peroxisome proliferator-activated receptor alpha (PPAR alpha), peroxisome proliferator-activated receptor gamma coactivator-1 (PGC1), and carnitine palmitoyltransferase 1 (CPT1). We used the animal model of PCOS obtained by treating female rats with dihydrotestosterone (DHT). Protein levels of CD36, lipin 1, PPAR alpha, PGC1, and antioxidative enzymes were assessed by Western blot in different cardiac cell compartments. Cardiac triglycerides (TG) and lipid peroxidation were also measured. The content of CD36 was decreased in both the cardiac plasma membranes and intracellular pool. On the other hand, total content of cardiac lipin 1 in DHT-treated rats was elevated, in contrast to decreased microsomal lipin 1 content. An increase in nuclear content of lipin 1 was observed together with elevation of nuclear PPAR alpha and PGC1, and an increase in CPT1 expression. However, lipid peroxidation was reduced in the heart, without alterations in antioxidative enzymes expression and cardiac TG content. The results indicate that treatment of female rats with DHT is accompanied by a decrease of fatty acid uptake and a reduction of lipid peroxidation in the heart. The observed elevation of lipin 1, PPAR alpha, PGC1, and CPT1 expression suggests that cardiac fatty acid metabolism is shifted toward mitochondrial beta oxidation.Ministry of Education, Science and Technological Development, Republic of Serbia {[}III41009

The influence of combined oral contraceptives containing drospirenone on hypothalamic-pituitary-adrenocortical axis activity and glucocorticoid receptor expression and function in women with polycystic ovary syndrome

OBJECTIVE: Most women with PCOS have increased adrenal androgen production, enhanced peripheral metabolism of cortisol and elevation in urinary excretion of its metabolites. Increased cortisol clearance in PCOS is followed by a compensatory overdrive of the hypothalamic-pituitary-adrenocortical (HPA) axis. We hypothesized that oral contraceptives containing ethinylestradiol and drospirenone (EE-DRSP) could modulate glucocorticoid receptor (GR) expression and function and thus affect HPA axis activity in PCOS patients. DESIGN: We analyzed 12 women with PCOS (age 24.17 +/- 4.88 years; body mass index 22.05 +/- 3.97 kg/m(2)) treated for 12 months with EE-DRSP and 20 BMI matched controls. In all subjects testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone binding globulin (SHBG), cortisol (basal and after dexamethasone), concentrations of GR protein, phospo-GR211 protein, number of GR per cell (B-max) and its equilibrium dissociation constant (K-D) were measured. RESULTS: Before treatment, increased concentrations of testosterone and DHEAS (p<0.001, respectively), unaltered basal cortisol and an increased sensitivity (p<0.05) of the HPA axis to dexamethasone were observed in PCOS women in comparison to controls. After treatment, testosterone (p<0.01), DHEAS (p<0.05) and cortisol suppression after dexamethasone (p<0.01) were decreased in PCOS women. There were no changes in GR protein concentration, GR phosphorylation nor in the receptor functional parameters B-max and K-D in women with PCOS before and after the therapy, and in comparison to controls. CONCLUSIONS: Prolonged treatment with EE-DRSP in PCOS women decreased serum androgens and increased cortisol in the presence of decreased sensitivity of the HPA axis and did not exert changes in GR expression and function.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}11141009

The influence of combined oral contraceptives containing drospirenone on hypothalamic-pituitary-adrenocortical axis activity and glucocorticoid receptor expression and function in women with polycystic ovary syndrome

OBJECTIVE: Most women with PCOS have increased adrenal androgen production, enhanced peripheral metabolism of cortisol and elevation in urinary excretion of its metabolites. Increased cortisol clearance in PCOS is followed by a compensatory overdrive of the hypothalamic-pituitary-adrenocortical (HPA) axis. We hypothesized that oral contraceptives containing ethinylestradiol and drospirenone (EE-DRSP) could modulate glucocorticoid receptor (GR) expression and function and thus affect HPA axis activity in PCOS patients. DESIGN: We analyzed 12 women with PCOS (age 24.17 +/- 4.88 years; body mass index 22.05 +/- 3.97 kg/m(2)) treated for 12 months with EE-DRSP and 20 BMI matched controls. In all subjects testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone binding globulin (SHBG), cortisol (basal and after dexamethasone), concentrations of GR protein, phospo-GR211 protein, number of GR per cell (B-max) and its equilibrium dissociation constant (K-D) were measured. RESULTS: Before treatment, increased concentrations of testosterone and DHEAS (p<0.001, respectively), unaltered basal cortisol and an increased sensitivity (p<0.05) of the HPA axis to dexamethasone were observed in PCOS women in comparison to controls. After treatment, testosterone (p<0.01), DHEAS (p<0.05) and cortisol suppression after dexamethasone (p<0.01) were decreased in PCOS women. There were no changes in GR protein concentration, GR phosphorylation nor in the receptor functional parameters B-max and K-D in women with PCOS before and after the therapy, and in comparison to controls. CONCLUSIONS: Prolonged treatment with EE-DRSP in PCOS women decreased serum androgens and increased cortisol in the presence of decreased sensitivity of the HPA axis and did not exert changes in GR expression and function.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}11141009