Enberg Ulla, Volpe Cristina, Hamberger Bertil
Department of Surgical Sciences and Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
Neurochem Res. 2003 Feb;28(2):327-32. doi: 10.1023/a:1022341619943.
The adrenal cortex synthesizes and releases steroid hormones, mainly mineralocorticoids and glucocorticoids. There is a functional zonation of the adrenal cortex and steroid synthesis is thoroughly regulated. Overproduction of aldosterone, primary aldosteronism, may be much more common than previously known and may be responsible for 10% of essential hypertension. Primary aldosteronism is characterized by autonomous production of aldosterone, suppressed renin activity, hypokalemia, and hypertension. The two most common forms are unilateral adenoma and bilateral hyperplasia. In spite of thorough clinical workup and careful histopathology it is often difficult to differentiate between adenoma and hyperplasia. The gene CYP11B2 encodes the steroid synthesizing enzymes for aldosterone production, while the genes CYP17 and CYP11B1 are needed for cortisol production. Most normal controls show expression of CYP11B2 in zona glomerulosa. Expression of CYP11B1 and CYP17 is seen in zona fasciculata and reticularis, whereas the expression of CYP21 is present in all three cortical layers. Adenomas from patients with primary aldosteronism show considerable variation in the expression of CYP11B2. Adenomas from patients with Cushing's syndrome have a strong expression of CYP11B1 and CYP17. In a patient material of 29 cases of primary aldosteronism, 4 patients had small nodules detected with expression of CYP11B2 gene. These nodules were not visualized on CT, whereas adrenal masses seen on CT in these patients showed CYP11B1 and CYP17 gene expression. This suggests that these small nodules are responsible for the aldosterone production and this is characteristic of nodular hyperplasia in patients with primary aldosteronism. In conclusion, this method to visualize mRNA gene expression of steroidogenic enzymes, and especially expression of CYP11B2, has increased the knowledge of adrenal pathophysiology. The results emphasize the value to include functional studies (venous sampling and/or scintigraphy) in the preoperative work up of patients with primary aldosteronism.
肾上腺皮质合成并释放类固醇激素，主要是盐皮质激素和糖皮质激素。肾上腺皮质存在功能分区，类固醇合成受到严格调控。醛固酮分泌过多，即原发性醛固酮增多症，可能比之前认为的更为常见，可能导致10%的原发性高血压。原发性醛固酮增多症的特征是醛固酮自主分泌、肾素活性受抑制、低钾血症和高血压。最常见的两种形式是单侧腺瘤和双侧增生。尽管进行了全面的临床检查和仔细的组织病理学检查，但腺瘤和增生之间的区分往往很困难。CYP11B2基因编码醛固酮生成所需的类固醇合成酶，而CYP17和CYP11B1基因是皮质醇生成所必需的。大多数正常对照在球状带显示CYP11B2的表达。CYP11B1和CYP17的表达见于束状带和网状带，而CYP21的表达存在于所有三个皮质层。原发性醛固酮增多症患者的腺瘤在CYP11B2的表达上有很大差异。库欣综合征患者的腺瘤有CYP11B1和CYP17的强表达。在29例原发性醛固酮增多症患者的病例材料中，4例患者检测到有CYP11B2基因表达的小结节。这些小结节在CT上不可见，而这些患者CT上看到的肾上腺肿块显示CYP11B1和CYP17基因表达。这表明这些小结节是醛固酮产生的原因，这是原发性醛固酮增多症患者结节性增生的特征。总之，这种可视化类固醇生成酶mRNA基因表达的方法，尤其是CYP11B2的表达，增加了对肾上腺病理生理学的认识。结果强调了在原发性醛固酮增多症患者术前检查中纳入功能研究（静脉采血和/或闪烁显像）的价值。
