ESTROGEN AND PROGESTERONE RECEPTORS OF THE OUT-OF-PHASE ENDOMETRIUM IN FEMALE INFERTILE PATIENTS

Objective: To examine the role of steroid hormone receptor compartmentalization in infertile women with ''in-phase'' or ''out-of-phase'' endometrium. Design: Nonrandomized prospective clinical study. Setting: A university clinic. Patients: Twenty-nine infertile patients without evidence of endometriosis, tubal factor, male factor, galactorrhea, or hyperandrogenism were enrolled. Sixteen patients had in-phase endometrium and a P level greater than or equal to 10 ng/mL (conversion factor to SI unit, 3.18) (group A). Four patients had out-of-phase endometrium and a P level > 10 ng/mL (group B). Four patients had in-phase endometrium and a P level < 10 ng/mL (group C), and five patients had out-of-phase endometrium and a P level < 10 ng/mL (group D). Main Outcome Measures: Each patient underwent determination of serum P and endometrial sampling on postovulatory days 6 to 9 based on serum LH measurement. Dating according to endometrial histology and biochemical assessment of estrogen receptor (ER) and P receptor (PR) were performed on each sample. Results: The level of cytosol ER was significantly lower in out-of-phase endometrium regardless of serum P level. There were no significant differences in the levels of cytosol PR and nuclear ER and PR among groups. In a long-term follow-up study, 6 of 29 patients became pregnant. The cytosol ER:PR ratio in these patients was found to fit a single straight regression line (y = 0.34x - 2.2). Conclusion: Out-of-phase endometrium probably depends on inadequate cytosol ER. An appropriate cytosol ER:PR ratio may be important to become pregnant.