Thymidine sale br Materials and methods br Results br Discus

Materials and methods
Results
Discussion Both EP2 and EP4 receptors were expressed in the horse oviduct in epithelial cells, vascular endothelium, smooth muscle and serosa. There was no evidence in the current study for differential regulation of EP2 or EP4 between estrus, diestrus or prior to puberty based upon relative amounts of mRNA and IHC for these receptors which suggests that these receptors may not be regulated by steroid environment or estrous cycle stage in the horse oviduct. Relatively few studies have examined the impact of estrous cycle stage or steroid environment on the expression of PGE2 receptor genes in the oviduct. In the human fallopian tube, expression of EP1, EP2 and EP3 genes was increased by administration of the synthetic progestin, levonorgestel (Wanggren et al., 2008), and EP2 gene expression was decreased after administration of the progesterone receptor antagonist, mifepristone (Wanggren et al., 2006). In cattle, EP2 and EP4 gene expression were greater in the pre-ovulatory phase than during the luteal phase in oviductal epithelial Thymidine sale recovered from abattoir material (Gabler et al., 2008). In mice, the EP2 receptor has a progesterone-responsive region in the 5′-flanking region of the gene (Tsuchiya et al., 2003), although evidence for differential regulation of EP2 gene expression in the oviduct of mice appears lacking. A number of studies suggest that estradiol and progesterone regulate expression of PGE2 receptors in the uterus. The uterine expression of EP2 was upregulated by progesterone or the combination of progesterone/estradiol in mice (Lim and Dey, 1997) and in rats (Blesson et al., 2012). Together, these studies suggest that expression of EP2 receptor genes is regulated by combinations of progesterone and estradiol; however, the available data do not clearly establish steroid-dependent regulation of EP2 within the oviduct across species. In the horse oviduct, the EP2 receptor was most strongly expressed in epithelial cells particularly in nonciliated (secretory) epithelial cells as evidenced by IHC. Furthermore, relative amount of EP2 mRNA was greater in the ampulla than in the isthmus, although this likely reflects differences in the relative abundance of mucosa in each of these regions as the epithelia were not separated from the muscularis prior to isolation of RNA in the present study. The distinct immunolocalization of EP2 suggests a possible role in regulation of epithelial secretory function in the horse oviduct (Desantis et al., 2011). Evidence in EP2−/− mice demonstrates a clear role for EP2 in fertility with a reduction in cumulus expansion, reduced ovulation and impaired fertilization (Hizaki et al., 1999, Kennedy et al., 1999). Although much of the effect on fertility in EP2−/− mice was attributed to poor expansion of the cumulus and reduced fertilization rates, it appears likely that alteration in oviductal function may also contribute to the effects of the EP2 knockout in mice.