Polycystic ovary syndrome (PCOS) is an endocrine-metabolic disorder associated with insulin resistance and compensatory hyperinsulinemia. Scarce information is available on the expression of molecules involved in the insulin pathway in endometria from women with PCOS. Therefore, we examined the protein levels of insulin-signaling molecules, like insulin receptor, insulin-receptor substrate (IRS)-1, pIRS-1Y612, Akt, AS160, pAS160T642 and GLUT4 in endometria from PCOS women with or without hyperinsulinemia. Protein levels were assessed by Western blot and immunohistochemistry in 21 proliferative-phase endometria from control women (CE = 7), normoinssulinemic PCOS women (PCOSE-NI = 7) and hyperinsulinemic PCOS women (PCOSE-HI = 7). The data show no differences in the expression of insulin receptor between all groups as assessed by Western blot; however, IRS-1 and pIRS-1Y612 were lower in PCOSE-HI than controls and PCOSE-NI (P < 0.05). AS160 was detected in all analyzed tissues with similar expression levels between groups. Importantly, PCOSE-HI exhibited lower levels of pAS160T642 (P < 0.05) and of GLUT4 (P < 0.05) compared with CE. The immunohistochemistry for insulin receptor, IRS-1, Akt, AS160 and GLUT4 showed epithelial and stromal localization; IRS-1 staining was lower in PCOSE-HI (P < 0.05). In conclusion, human endometrium has the machinery for glucose uptake mediated by insulin. The diminished expression of GLUT4, as well as the lower level of pIRS-1Y612 and pAS160T642 exhibited by PCOSE-HI, suggests a disruption in the translocation of vesicles with GLUT4 to the cell surface in these patients.

PCA restores the insulin responsiveness of OB-VAT by increasing IRS-1 and Akt phosphorylation which could be related with the lower PTP1B activity found in PCA-treated OB-VAT. Furthermore, PCA diminishes inflammation in VAT. These results support the beneficial role of an anthocyanin-rich diet against inflammation and insulin resistance in obesity.

BackgroundPolycystic Ovary Syndrome (PCOS) is an endocrine-metabolic disorder commonly associated with insulin resistance (IR). Previous studies indicate about the expression of molecules involved in the insulin pathway in endometria of women with PCOS-IR. Therefore, the aim of the present study was to evaluate the effect of insulin and testosterone in the expression of these proteins in the endometria and immortal endometrial stromal cell line (T-HESCs).MethodsWe examined the protein levels of Munc18c, PKC zeta, phospho-PKC Zeta, and Syntaxin-4. Protein levels were assessed by Western Blot and/or immunohistochemistry in proliferative endometria (NPE = 6) and in PCOS endometria with insulin resistance (PCOSE-IR = 6). We also evaluated whether high concentrations of insulin (100 nM) and/or testosterone (100 nM), during a 24 h stimulatory period, affected the expression of these proteins in an immortal endometrial stromal cell line (T-HESCs). Once stimulated, proteins were extracted from cells and were assessed by Western Blot analysis. Immunocytochemistry was performed to detect AR in T-HESC cells.ResultsWestern Blot data showed decreased expression (p < 0,05) of Munc18c and phospho-PKC Zeta in PCOS-IR endometria (PCOSE-IR) with respect to the control (NPE). In the in vitro study, Western Blot analysis showed decreased levels of Munc18c, PKC Zeta and phospho-PKC Zeta with the different hormonal treatments when compared to the control condition (no hormonal stimulation) (p < 0,05). The AR was present in the endometrial stromal cell line (T-HESC).ConclusionThe conditions of hyperinsulinism and hyperandrogenism present in PCOS-IR patients modulate the expression and/or phosphorylation of the proteins involved in the insulin pathway at the endometrial level. These data extend to the T-HESCs cells results, where insulin and testosterone exert an effect on both the expression and phosphorylation of proteins present in the pathway.