Shimojo M, Ricketts M L, Petrelli M D, Moradi P, Johnson G D, Bradwell A R, Hewison M, Howie A J, Stewart P M
Department of Medicine, University of Birmingham, Queen Elizabeth Hospital, Edgbaston, United Kingdom.
Endocrinology. 1997 Mar;138(3):1305-11. doi: 10.1210/endo.138.3.4994.
11 beta-Hydroxysteroid dehydrogenase (11 beta HSI) is an enzyme complex responsible for the conversion of hormonally active cortisol to inactive cortisone; two isoforms of the enzyme have been cloned and characterized. Clinical observations from patients with the hypertensive syndrome apparent mineralocorticoid excess, recently explained on the basis of mutations in the human 11 beta HSD2 gene, suggest that it is the 11 beta HSD2 isoform that serves a vital role in dictating specificity upon the mineralocorticoid receptor (MR). We have raised a novel antibody in sheep against human 11 beta HSD2 using synthetic multiantigenic peptides and have examined the localization and subcellular distribution of 11 beta HSD2 in mineralocorticoid target tissues. The immunopurified antibody recognized a single band of approximately 44 kDa in placenta, trophoblast, and distal colon. In kidney tissue, two bands of approximately 44 and 48 kDa were consistently observed. No signal was seen in decidua, adrenal, or liver. Immunoperoxidase studies on the mineralocorticoid target tissues, kidney, colon, and parotid gland indicated positive staining in epithelial cells known to express the MR: respectively, renal collecting ducts, surface and crypt colonic epithelial cells, and parotid duct epithelial cells. No staining was seen in these tissues in other sites. The intracellular localization of 11 beta HSD2 in kidney and colon epithelial cells was addressed using confocal laser microscopy. Parallel measurements of 11 beta HSD2 and nuclear propidium iodide fluorescence on sections scanned through an optical section of approximately 0.1 micron indicated significant 11 beta HSD2 immunofluorescence in the nucleus. In human kidney, colon, and salivary gland, 11 beta HSD2 protects the MR from glucocorticoid excess in an autocrine fashion. Furthermore, within these tissues, 11 beta HSD2, which had been considered to be a microsomal enzyme, is also found in the nucleus, suggesting that the interaction between the MR and aldosterone or cortisol is in part a nuclear event.
11β-羟基类固醇脱氢酶（11β-HSI）是一种负责将具有激素活性的皮质醇转化为无活性可的松的酶复合物；该酶的两种同工型已被克隆并鉴定。近期基于人类11β-HSD2基因突变对明显盐皮质激素过多的高血压综合征患者进行的临床观察表明，正是11β-HSD2同工型在决定盐皮质激素受体（MR）的特异性方面发挥着至关重要的作用。我们利用合成多抗原肽在绵羊体内制备了一种针对人类11β-HSD2的新型抗体，并研究了11β-HSD2在盐皮质激素靶组织中的定位和亚细胞分布。免疫纯化的抗体在胎盘、滋养层和远端结肠中识别出一条约44 kDa的单带。在肾组织中，始终观察到两条约44 kDa和48 kDa的条带。在蜕膜、肾上腺或肝脏中未检测到信号。对盐皮质激素靶组织肾脏、结肠和腮腺进行的免疫过氧化物酶研究表明，在已知表达MR的上皮细胞中呈阳性染色：分别为肾集合管、结肠表面和隐窝上皮细胞以及腮腺导管上皮细胞。在这些组织的其他部位未观察到染色。使用共聚焦激光显微镜研究了11β-HSD2在肾脏和结肠上皮细胞中的细胞内定位。在扫描厚度约为0.1微米的光学切片上对11β-HSD2和核碘化丙啶荧光进行平行测量，结果表明在细胞核中有明显的11β-HSD2免疫荧光。在人类肾脏、结肠和唾液腺中，11β-HSD2以自分泌方式保护MR免受糖皮质激素过量的影响。此外，在这些组织中，11β-HSD2（一直被认为是一种微粒体酶）也存在于细胞核中，这表明MR与醛固酮或皮质醇之间的相互作用部分是一个核事件。
