101. Decreased Phosphorylation of Y 14Caveolin-1 in Endometrial Tissue of Polycystic Ovary Syndrome Patients may be Related with an Insulin Resistant State in this Tissue.
- Author
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Ormazabal, P., Romero, C., Gabler, F., Quest, A. F. G., and Vega, M.
- Subjects
CAVEOLINS ,PHOSPHORYLATION ,POLYCYSTIC ovary syndrome ,INSULIN resistance ,GLUCOSE in the body ,GLUCOSE metabolism ,TYROSINE ,INSULIN receptors - Abstract
Endometrial tissue of patients with polycystic ovary syndrome (PCOS) shows an impaired expression of insulin signaling molecules. Tyrosine phosphorylation of the insulin receptor (IR) by insulin promotes glucose uptake by activating the PI3K/Akt pathway. IR stability and function depend on the presence of the protein caveolin- 1. Activation of IR increases phosphorylation of Y
14 caveolin-1. Since the endometrium of PCOS patients is proposed to be insulin resistant, we evaluated the phosphorylation of IR and caveolin-1 in endometria of patients with insulin resistance (PCOSE-IR) compared to controls (CE). To explore the mechanism associated with this condition, cultured endometrial cells (T-HESC) were exposed to high glucose (25 mM, 24 h), an experimental condition that leads to insulin resistance in other cell types. Endometrial protein levels of phospho-Y972 IR, phospho- Y14 caveolin-1 and caveolin-1 were determined by Western blotting. In cultured cells, protein levels of caveolin-1, IR, and Akt were evaluated by Western blotting. After acute insulin stimulation, phospho-S473 Akt, phospho-Y14 caveolin-1, and 2-deoxyglucose (2-DOG) uptake were determined. PCOSE-IR samples showed high protein levels of caveolin-1, but reduced phospho-Y14 caveolin- 1 compared to CE. No diff erences were observed for phospho-Y972 IR between both groups. Cells pretreated with glucose showed a reduction in protein levels of IR and caveolin-1 and were unable to increase 2-DOG uptake, phosphor-S473 Akt and phospho-Y14 caveolin-1 after insulin stimulation. In conclusion, in PCOSE-IR the impaired phosphorylation of IR downstream molecules such as phospho-Y14 caveolin-1 suggests a diminished insulin sensitivity in endometria, condition that could be supported in vitro by the ability of T-HESCs to become insulin resistant when they are exposed to high glucose. [ABSTRACT FROM AUTHOR]- Published
- 2013
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