Endometrial cytokine expression is poorly understood. T-Bet and GATA-3 regulate cytokine expression in T-lymphocytes. Previous work has demonstrated expression of T-Bet in human endometrium. Changes in human endometrial T-Bet and GATA-3 mRNA and protein expression during the normal menstrual cycle were characterized. Human endometrium from each phase of the menstrual cycle underwent real-time reverse-transcriptase polymerase chain reaction and immunohistochemistry to examine expression and localization. T-Bet and GATA-3 mRNA were increased in the late secretory phase. Progesterone receptor (PR) mRNA was increased during the proliferative and early secretory phases. T-Bet and GATA-3 proteins localized cytoplasmically in the late secretory phase. PR protein displayed nuclear localization and maximal immunostaining during the early secretory phase. T-Bet and GATA-3 are expressed in endometrial epithelium cyclically during the menstrual cycle. T-Bet and GATA-3 are both upregulated during the late secretory phase and in the same cell types. The expression patterns of T-Bet and GATA-3 oppose PR, suggesting antagonistic function and/or regulation between PR and T-Bet/GATA-3
