Abstract

Objective.: To study if the endocrinological status of PCOS women affects the endometrial sensitivity to steroids by evaluating the expression of androgen receptor (AR), estrogen receptor α (ERα), estrogen receptor β (ERβ), co-activators AIB1 and ARA70, and co-repressor NCoR. Methods.: Gene and/or protein expression of steroid receptors and co-regulators was measured in 17 samples of normal endometrium (NE), 23 PCOS endometrium without treatment (PCOSE), 11 endometria from PCOS women and with endometrial hyperplasia (HPCOSE), and 10 endometria from patients with endometrial hyperplasia (HE), using RT-PCR and/or immunohistochemistry and Western blot. Results.: Gene and protein expression of AR was relatively elevated in PCOSE and HPCOSE compared with NE. A significant increase in ERα protein expression was observed in PCOSE, preferentially in the nucleus of endometrial cells, whereas ERβ gene and protein expression increased gradually from PCOSE to HPCOSE and HE, mainly in the epithelial compartment. Importantly, we found a gradual increase in the ERβ/ERα gene and protein expression ratio in endometria from the four groups of women. AIB1 showed increased nuclear protein expression in PCOSE compared to NE, in the presence of a high expression of ARA70 in all groups. High expression of ARA70 together with a normal expression level of AIB1 was observed in HPCOSE. The cytoplasmic immunostaining of NCoR was similar between the four groups of patients. Conclusion.: The PCOS endometrium exhibits a higher sensitivity to steroid action. We can inferred that these alterations could deregulate the transcription of genes involved in the cell cycle, which may lead to the development of endometrial hyperplasia in PCOS women. © 2006 Elsevier Inc. All rights reserved.