Walmer D K, Wrona M A, Hughes C L, Nelson K G
Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, North Carolina 27710.
Endocrinology. 1992 Sep;131(3):1458-66. doi: 10.1210/endo.131.3.1505477.
Lactoferrin (LTF), an iron-binding glycoprotein present in most exocrine secretions and in the secondary granules of polymorphonuclear leucocytes (PMN), is regulated by estrogen in the mouse reproductive tract. We investigated the expression of LTF mRNA and protein during the natural estrous cycle to increase our understanding of how this uterine secretory protein is regulated under physiological conditions. There was a positive correlation between LTF mRNA expression in the genital tract and serum estradiol (E2) concentrations. When E2 peaked in proestrus, LTF mRNA and protein were expressed in the uterus; however, during metestrus, when both E2 and progesterone levels were high, LTF mRNA was expressed, while LTF protein was decreasing. LTF protein expression may be hindered by progesterone or some other local factor in the endometrial epithelium after ovulation. Immunohistochemistry demonstrated two distinct staining patterns for LTF in the vaginal and endometrial epithelium. In one staining pattern, the colorimetric reaction was noted over the cytoplasm, and in the other, the nuclear region stained more intensely. This suggests the possibility that in addition to its known role as a secretory protein, LTF may be transported to the nucleus, serving an autocrine role. Our results also indicated that LTF protein is a useful marker for tracking PMN. Nonproliferating epithelial cells in the vagina and endometrium may synthesize chemotactic and/or adhesion molecules for PMN.
乳铁蛋白（LTF）是一种存在于大多数外分泌液和多形核白细胞（PMN）次级颗粒中的铁结合糖蛋白，在小鼠生殖道中受雌激素调节。我们研究了自然发情周期中LTF mRNA和蛋白的表达，以增进我们对这种子宫分泌蛋白在生理条件下如何调节的理解。生殖道中LTF mRNA表达与血清雌二醇（E2）浓度之间存在正相关。当E2在发情前期达到峰值时，LTF mRNA和蛋白在子宫中表达；然而，在发情后期，当E2和孕酮水平都很高时，LTF mRNA表达，而LTF蛋白在减少。排卵后，孕酮或子宫内膜上皮中的其他一些局部因素可能会阻碍LTF蛋白的表达。免疫组织化学显示LTF在阴道和子宫内膜上皮中有两种不同的染色模式。在一种染色模式中，比色反应出现在细胞质上，而在另一种模式中，核区域染色更强烈。这表明除了其作为分泌蛋白的已知作用外，LTF可能被转运到细胞核，发挥自分泌作用。我们的结果还表明，LTF蛋白是追踪PMN的有用标志物。阴道和子宫内膜中的非增殖上皮细胞可能合成PMN的趋化和/或黏附分子。
