Chen L M, Chung P, Chao S, Chao L, Chao J
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston 29425.
Biochim Biophys Acta. 1992 Jun 15;1131(2):145-51. doi: 10.1016/0167-4781(92)90069-c.
Kininogens which have multifunctional domains, serve as the precursors of potent vasoactive kinin peptides and also function as cysteine proteinase inhibitors. Given its potential role in blood pressure homeostasis and inflammation, we have examined the regulation of rat kininogen gene expression by sex hormones in vivo. Our studies indicate a differential regulation of kininogen gene expression in rat liver by estrogen and progesterone. Northern and dot blot analysis using a rat low molecular weight kininogen cDNA probe show that kininogen mRNA levels in the liver of female rats are 4-fold higher than those in male rats. Ovariectomy results in a reduction of kininogen transcripts in the liver, while estradiol replacement of the ovariectomized rats increases kininogen mRNA levels. Similarly, Northern blot analysis using a kallikrein cDNA probe shows that estradiol treatment induces an increase of kallikrein gene expression in the kidney of the same animals. In contrast, progesterone treatment of the ovariectomized rats results in an increase in renal kallikrein mRNA levels while it reduces kininogen gene expression as compared to vehicle-treated ovariectomized animals. Immunoreactive kininogen levels in the serum, analyzed by a direct radioimmunoassay and Western blot, are increased by estradiol but slightly decreased by progesterone treatment. Western blot of serum proteins on a two-dimensional polyacrylamide gel reveals that in estradiol-treated ovariectomized rats, the levels of several 68,000 Da kininogens varying in charge are markedly higher than those in ovariectomized rats. The results indicate that estrogen is one of the determinants in regulating low molecular weight kininogen gene expression in vivo. The impact of estrogen-regulated kininogen expression on cardiovascular function awaits further investigation.
具有多功能结构域的激肽原，作为强效血管活性激肽肽的前体，还具有半胱氨酸蛋白酶抑制剂的功能。鉴于其在血压稳态和炎症中的潜在作用，我们研究了性激素在体内对大鼠激肽原基因表达的调控。我们的研究表明，雌激素和孕酮对大鼠肝脏中激肽原基因表达的调控存在差异。使用大鼠低分子量激肽原cDNA探针进行的Northern印迹和斑点印迹分析表明，雌性大鼠肝脏中的激肽原mRNA水平比雄性大鼠高4倍。卵巢切除导致肝脏中激肽原转录本减少，而给卵巢切除的大鼠补充雌二醇可增加激肽原mRNA水平。同样，使用激肽释放酶cDNA探针进行的Northern印迹分析表明，雌二醇处理可诱导同一动物肾脏中激肽释放酶基因表达增加。相比之下，给卵巢切除的大鼠注射孕酮会导致肾脏中激肽释放酶mRNA水平增加，而与注射溶剂的卵巢切除动物相比，它会降低激肽原基因表达。通过直接放射免疫测定和Western印迹分析血清中的免疫反应性激肽原水平，结果显示雌二醇可使其升高，而孕酮处理则使其略有降低。在二维聚丙烯酰胺凝胶上对血清蛋白进行Western印迹分析显示，在经雌二醇处理的卵巢切除大鼠中，几种电荷不同的68,000 Da激肽原的水平明显高于卵巢切除大鼠。结果表明，雌激素是体内调节低分子量激肽原基因表达的决定因素之一。雌激素调节的激肽原表达对心血管功能的影响有待进一步研究。
