An Beum-Soo, Choi Kyung-Chul, Kang Sung Keun, Lee Geun-Shik, Hong Eui-Ju, Hwang Woo Suk, Jeung Eui-Bae
College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763 Chungbuk, Republic of Korea.
Mol Cell Endocrinol. 2003 Jul 31;205(1-2):79-88. doi: 10.1016/s0303-7207(03)00203-x.
Calbindin-D(9k) (CaBP-9k) is a cytosolic calcium binding protein mainly expressed in duodenum, placenta and uterus. In order to understand the expression pattern and regulation of uterine CaBP-9k gene, the expression of CaBP-9k mRNA and its regulation by estrogen (E2) and progesterone (P4) were investigated in the mouse uterus during late pregnancy (from day 12 to 18) and lactation. The expression levels of uterine CaBP-9k, estrogen receptor alpha (ERalpha) and progesterone receptor (PR) mRNAs were measured by Northern blot analysis. The expression levels of mouse uterine CaBP-9k mRNA gradually increased from pregnancy day 16 (P16), peaked at P18 (6.0-fold vs. P12) and declined at birth and during lactation. The expression levels of ERalpha and PR mRNAs indicated a similar fluctuation as CaBP-9k mRNA, suggesting the role of sex steroids/receptors in the regulation of CaBP-9k gene. To investigate effect of steroid hormone on CaBP-9k mRNA expression, three groups of animals were injected (s.c) with steroid hormone antagonists (RU486, tamoxifen, and ICI182780), respectively. RU486, a P4 antagonist, induced a significant decrease in CaBP-9k mRNA expression at 48 (3.2-fold) and 72 h (3.8-fold). However, tamoxifen and ICI182780, E2 antagonists, had no effect on CaBP-9k mRNA expression. Combined treatment with RU486 and ICI182780 did not further decrease the expression level of CaBP-9k mRNA when compared with RU486 treatment at 48 and 72 h. In addition, the treatment with RU40555, a glucocorticoid/progesterone antagonist, resulted in a decrease at 48 and 72 h following treatment. These results indicate that E2 is not likely involved in the regulation of CaBP-9k gene in the mouse uterus during late pregnancy and lactation. In conclusion, the present results suggest that P4, not E2 is a key regulator of CaBP-9k mRNA expression during late pregnancy and lactation.
钙结合蛋白-D（9k）（CaBP-9k）是一种主要在十二指肠、胎盘和子宫中表达的胞质钙结合蛋白。为了解子宫CaBP-9k基因的表达模式及其调控机制，我们研究了妊娠后期（第12至18天）和哺乳期小鼠子宫中CaBP-9k mRNA的表达情况以及雌激素（E2）和孕酮（P4）对其的调控作用。通过Northern印迹分析测定子宫CaBP-9k、雌激素受体α（ERα）和孕酮受体（PR）mRNA的表达水平。小鼠子宫CaBP-9k mRNA的表达水平从妊娠第16天（P16）开始逐渐升高，在P18时达到峰值（相较于P12增加了6.0倍），并在出生时和哺乳期下降。ERα和PR mRNA的表达水平呈现出与CaBP-9k mRNA相似的波动，表明性类固醇/受体在CaBP-9k基因调控中发挥作用。为研究类固醇激素对CaBP-9k mRNA表达的影响，将三组动物分别皮下注射类固醇激素拮抗剂（RU486、他莫昔芬和ICI182780）。P4拮抗剂RU486在48小时（3.2倍）和72小时（3.8倍）时显著降低了CaBP-9k mRNA的表达。然而，E2拮抗剂他莫昔芬和ICI182780对CaBP-9k mRNA的表达没有影响。与48小时和72小时的RU486处理相比，RU486和ICI182780联合处理并未进一步降低CaBP-9k mRNA的表达水平。此外，糖皮质激素/孕酮拮抗剂RU40555处理在处理后48小时和72小时导致表达下降。这些结果表明，在妊娠后期和哺乳期，E2不太可能参与小鼠子宫中CaBP-9k基因的调控。总之，目前的结果表明，在妊娠后期和哺乳期，P4而非E2是CaBP-9k mRNA表达的关键调节因子。
