Yun So-Mi, Choi Kyung-Chul, Kim Ill-Hwa, An Beum-Soo, Lee Geun-Shik, Hong Eui-Ju, Oh Goo-Taeg, Jeung Eui-Bae
Laboratory of Veterinary Molecular Biology & Biochemistry, College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea.
Mol Reprod Dev. 2004 Mar;67(3):251-6. doi: 10.1002/mrd.20019.
Calbindin-D9k (CaBP-9k) is a member of intracellular calcium binding proteins, which have a high affinity to calcium. CaBP-9k is mainly expressed in the mammalian intestine, uterus and placenta, and is regulated in tissue- and species-specific manners. Previous studies have shown that CaBP-9k expression is mainly controlled by steroid hormones and their receptors. Thus, we further investigated the expression and regulation of CaBP-9k during an estrus cycle in the pig uterus by Northern blot and immunoblot analysis in this study. In addition, serum levels of estrogen (E2) and progesterone (P4) were measured using ELISA. The CaBP-9k mRNA is highly expressed in the porcine uterus during a luteal phase compared to a follicular phase, and its mRNA level in a luteal phase is increased up to 10-fold compared to a follicular phase. In parallel to the level of CaBP-9k mRNA, the CaBP-9k protein is also dominantly expressed in the porcine uterus, and strongly expressed in the epithelium and glands of the porcine uterus during a luteal phase. Although, the localization of the CaBP-9k protein is scarcely detected at follicular phase, it is dominantly expressed in the porcine uterus during a luteal phase. In addition, the serum P4 level was significantly increased during a luteal phase compared to a follicular phase, whereas no difference was observed in E2 levels between follicular and luteal phases, indicating that the ratio of P4/E2 is remarkably increased in porcine uterus during a luteal phase compared to a follicular phase. In conclusion, these results suggest that P4 may play an important role in the up-regulation of CaBP-9k gene in the porcine uterus in a luteal phase, which is unlike the condition in the rat uterus. In addition, the porcine CaBP-9k may be dominantly expressed in the epithelium and glandular structure of pig uterus during a luteal phase. It may also be differentially regulated during this cycle presumably by steroid hormones, especially up-regulated P4 levels in this tissue.
钙结合蛋白-D9k（CaBP-9k）是细胞内钙结合蛋白家族的一员，对钙具有高亲和力。CaBP-9k主要在哺乳动物的肠道、子宫和胎盘中表达，并以组织和物种特异性的方式受到调控。先前的研究表明，CaBP-9k的表达主要受类固醇激素及其受体的控制。因此，在本研究中，我们通过Northern印迹和免疫印迹分析进一步研究了猪子宫发情周期中CaBP-9k的表达和调控。此外，使用酶联免疫吸附测定法（ELISA）检测了血清中雌激素（E2）和孕酮（P4）的水平。与卵泡期相比，黄体期猪子宫中CaBP-9k mRNA的表达水平较高，其在黄体期的mRNA水平相较于卵泡期增加了10倍。与CaBP-9k mRNA水平一致，CaBP-9k蛋白在猪子宫中也占主导性表达，并且在黄体期猪子宫的上皮和腺体中强烈表达。虽然在卵泡期几乎检测不到CaBP-9k蛋白的定位，但在黄体期它在猪子宫中占主导性表达。此外，与卵泡期相比，黄体期血清P4水平显著升高，而卵泡期和黄体期之间E2水平未观察到差异，这表明与卵泡期相比，黄体期猪子宫中P4/E2的比值显著增加。总之，这些结果表明，P4可能在黄体期猪子宫中CaBP-9k基因的上调中起重要作用，这与大鼠子宫的情况不同。此外，猪CaBP-9k可能在黄体期猪子宫的上皮和腺结构中占主导性表达。在这个周期中，它可能也受到类固醇激素的差异调节，特别是该组织中P4水平的上调。
