We have demonstrated that COX-2 gene is the dominant isoform expressed in uterine tissues of advanced-pregnant cows and have provided evidence for the capacity of OT to induce expression of COX-2 mRNA in bovine endometrium in vivo. While this work was in progress, stimulation of COX-2 mRNA expression by OT in bovine endometrial cells in vitro and in the nonpregnant sheep uterus in vivo was reported. Together, these results implicate OT as a ligand that, similarly to several mitogens and cytokines, induces COX-2 gene transcription and mRNA accumulation in bovine and ovine endometrium. Previous results in prepubertal heifers have shown that the influence of progesterone is a prerequisite for OT-induced COX-2 gene expression.
COX-1 gene transcripts were rare and were detectable by RPA only sporadically in myometrium and caruncles, but not in the other tissues studied. The basal levels of COX-1 transcripts in the reproductive tissues of pregnant cows are apparently very low. Interestingly, the fetal uterus expressed COX-1 but not COX-2 mRNA, suggesting a developmental role for this isoform. Buy Advair Diskus Online
COX-2 mRNA was most highly expressed in cotyledons and caruncles, in which transcripts accumulated during the latter part of gestation without any exogenous stimulation. Mitogens and cytokines are known inducers of COX-2 transcription, and cotyledons and fetal membranes have the capacity to produce growth factors and other mitogens; therefore such fetal factors may be responsible for the accumulation of COX-2 transcripts in cotyledons.