The influence of tumor necrosis factor α (TNF) on the secretory function of bovine corpus luteum: TNF and its receptors expression during the estrous cycle

SUMMARY Tumor necrosis factor α (TNF) inversely regulates the function of bovine corpus luteum (CL). Whereas the low doses of TNF induce luteolysis, the high doses prolong CL lifespan and prevent luteolysis in vivo. We suggest that the varying effects of TNF may be caused by its action exerted on CL via multiple signaling pathways involving two distinct receptors: TNFR-I (responsible for induction of the cell death) and TNFR-II (implicated in cell proliferation). In the study, we determined CL expressions of TNF, TNFR-I and TNFR-II mRNAs during the bovine estrous cycle using semiquantitative RT-PCR. Specific transcripts for TNF, TNFR-I and TNFR-II were found in the CL with the highest (p