摘要 : The homeobox A (<i>HOXA</i>) family of genes is responsible for segmental development of the female reproductive tract during embryogenesis. However, <i>HOXA10</i> has been shown to be essential not only for uterus development, bu... 展开 The homeobox A (<i>HOXA</i>) family of genes is responsible for segmental development of the female reproductive tract during embryogenesis. However, <i>HOXA10</i> has been shown to be essential not only for uterus development, but also for implantation. Persistent expression and steroid-dependent regulation of this gene has been demonstrated in adult human, primate, murine and canine uteri. Moreover, <i>HOXA10</i>-dependent expression of prostaglandin H synthase-2 (PGHS-2), a key enzyme in prostaglandin production, has been previously detected. The role of the <i>HOXA10</i> gene in the porcine uterus is not well established. Therefore, the present studies were undertaken to (1) examine the effect of E₂ and P₄ on HOXA10 mRNA and protein content in the endometrium collected on day 9 of the estrous cycle and (2) determine the PGHS-2 protein expression and PGE₂ and PGF_{2 alpha} secretion from endometrial tissue in response to steroid treatment. Endometrial explants collected from mature gilts on day 9 of the estrous cycle were incubated with E₂ (1-100 nM), P₄ (10-1000 nM) or E₂ (10 nM) and P₄ (100 nM) for 24 h. E₂ alone or E₂ in the presence of P₄ increased <i>HOXA10</i> mRNA expression in the endometrium (P<0.05). The HOXA10 protein level was upregulated in response to E₂, P₄ and both steroids administered simultaneously (P<0.05). Moreover, E₂ and P₄ stimulated PGHS-2 protein expression in cultured endometrial explants. PGE₂, but not PGF_{2 alpha}, secretion increased in the presence of E₂ (P<0.05). However, the release of both prostaglandins was decreased after treatment of endometrial explants with the highest dose of P₄ (P<0.01). These results demonstrate that E₂ and P₄ are important regulators of <i>HOXA10</i> gene expression in the adult porcine endometrium during the mid-luteal phase of the estrous cycle. Additionally, the similar profiles of endometrial HOXA10 and PGHS-2 expression in the presence of E₂ and P₄ indicate that both genes are simultaneously regulated by steroids in the porcine uterus. 收起