Functional Investigation on Aromatase in Endometrial Hyperplasia in Polycystic Ovary Syndrome Cases

Objective: To explore the possible significance of aromatase P450 in endometrial hyperplasia with abackground of polycystic ovary syndrome (PCOS).
Methods: Immunohistochemistry was used to determine theexpression of aromatase P450 in endometrium of PCOS patients. Semiquantitative analysis of aromatase P450expression of mRNA and protein level wasalso carried out by real-time quantitative RT-PCR method. Afterendometrial cells were stimulated by testosterone and letrozole in vitro, the estradiol (E2) level was determined,and the expression of cell aromatase P450 mRNA was assessed.
Results: The aromatase P450 mRNA level wasincreased in endometria of PCOS patients. When endometrial cells were cultured with 10-6 M testosterone, theE2 level in the culture medium increased. An inhibitory effect on E2 generation and expression of aromataseP450 mRNA was observed when the endometrial cells were treated with 10-5 M letrozole.
Conclusions: There isan increased expression of aromatase P450 in PCOS patient endometrium. Androgen stimulation could enhancethe synthesis of aromatase P450 mRNA and the production of E2 in endometrial cells in vitro while letrozolecould do the reverse.