Localization of interferon regulatory factor-1 in human endometrium throughout the menstrual cycle.

OBJECTIVE: To determine the expression and localization of IRF-1 in human endometrium throughout the menstrual cycle.
DESIGN: A comparative study.
SETTING: Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine. PATIENTS: Thirty-eight women aged 33 to 46 years, with regular menstrual cycles and nonpathological endometrium, undergoing hysterectomy. INTERVENTION(S): Endometrial tissues were obtained from operative samples. MAIN OUTCOME MEASURE(S): Expression of IRF-1 mRNA throughout the menstrual cycle was investigated using semiquantitative reverse transcription-polymerase chain reaction. Localization of IRF-1 protein was determined using immunohistochemistry. RESULT(S): IRF-1 mRNA was expressed in the human endometrium at each phase of the menstrual cycle. The immunoreactivity for IRF-1 was observed in the extranuclear compartment of the surface and glandular epithelial cells, both during the proliferative and secretory phases, as well as in the gland secretion during the secretory phase. In contrast, stromal cells were nearly unstained. CONCLUSION(S): IRF-1 was localized in the human endometrium, implying that this nuclear protein plays some role other than as a transcription factor.