Tumor necrosis factor-alpha (TNF) messenger RNA (mRNA) and protein have been identified in the uteri of cycling rats, mice, and women. In this study, a mouse model was used to investigate the cell-specific expression and regulation of the TNF gene in the endometrium. Uteri from cycling and ovariectomized hormone-reconstituted mice were tested by in situ and Northern blot hybridizations as well as by immunohistochemistry. Cyclic variations were observed in TNF mRNA. Although weak to undetectable during proestrus, estrus, and diestrus-I, TNF mRNA was present in both epithelial and stromal cells on diestrus-II. TNF protein was observed in the endometrium on each day of the estrous cycle, primarily in the epithelial cells. Stromal TNF immunoreactivity was observed only during diestrus-I. Seven days after ovariectomy, TNF mRNA and protein were undetectable in the endometrium. Specific message and protein were restored in both epithelial and stromal cells after administration of 17 beta-estradiol (E2), progesterone (P4), and E2 plus P4. E2 treatment resulted in a biphasic pattern of TNF mRNA expression. mRNA was present in epithelial cells 1 and 6 h posttreatment, was not detectable after 24 h, and then was present in both the epithelium and stroma after 72 h. In contrast, TNF mRNA was detectable at all time points after P4 administration. TNF mRNA was localized to both the epithelium and stroma until 72 h of P4 treatment, when stromal TNF mRNA was no longer detectable. TNF mRNA was also present at all time points examined after the combination E2 and P4 treatment. TNF mRNA was invariably localized to the epithelium; however, stromal mRNA fluctuated over the course of treatment. TNF mRNA was in the stroma 1 and 24 h post-E2 plus P4 treatment, but was not present at the 6 and 72 h points. In general, the pattern of TNF protein matched that of the TNF mRNA, with a few exceptions. Twenty-four hours after E2 treatment, TNF mRNA was not detectable; however, TNF protein was present in the epithelium. The opposite was observed 24 h after E2 plus P4 administration when the epithelium and stroma contained TNF mRNA; however, no protein was observed. In addition, with the exception of 72 h of E2 treatment, stromal TNF protein was not abundant, although TNF mRNA was often detected. In summary, the results of this study indicate that both epithelial and stromal cells contain TNF mRNA and protein and that E2 and P4 exert individual influences on the cell-specific expression of TNF transcripts and protein.