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STUDY ON CARBONIC ANHYDRASE IN RENAL TUBULE EPITHELIA

肾小管上皮中碳酸酐酶的研究

基本信息

批准号：
06670826
负责人：
SATO Seiji
金额：
$ 1.34万
依托单位：
KEIO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Carbonic anhydrase IV (Ca IV) is a key enzyme in the bicarbonate reabsorption in proximal renal tubule. CA IV deficiency is possibly causative for some forms of proximal renal tubular acidosis. We investigated carbonic anhydrase in the patient suffered with persistent, pure proximal renal tubular acidosis.We studied carbonic anhydrase II (CA II) and IV in urinary membrane and soluble fractions in the patient and normal controls. Membrane-associated CA II of the patient was similar to that of normal controls in the immunochemical detection and activity measurement. Immunochemically detected membrane-associated CA IV was identical in the size in both the patient and normal controls, but much less in the band intensity in the patient than in normal controls. Soluble CA IV was much increased in the patient. These results suggested that the anchoring mechanism of CA IV to membrane may be abnormal and causative for proximal renal tubular acidosis in the patient. Alkalinephosphatase in urinary membrane fraction, which anchored to membrane via glycosyl-phosphatidylinositol as same as CA IV,was simultaneously studied and was normal. We speculated that subtle mutation in CA IV gene especially in C-terminal domain might be responsible for the disease.We amplified the 7 exons in CA IV gene with 7 sets of PCR primers constructed a ccording with the intronic sequence, and sequenced them using the PCR primer as sequence primer. No mutation was detected in the exon-intron boundaries and exons.We concluded that the mutation in CA IV was unlikely in the patient. The cause of the patient with persistent, pure proximal renal tublar acidosis is still remained to be elucidated.

碳酸酐酶IV （Ca IV）是近端肾小管重吸收碳酸氢盐的关键酶。CA - IV缺乏可能导致某些形式的肾近端小管酸中毒。我们研究了持续的纯近端肾小管酸中毒患者的碳酸酐酶。我们研究了患者和正常人尿膜和可溶组分中的碳酸酐酶II （CA II）和IV。在免疫化学检测和活性测量中，患者的膜相关CA II与正常对照相似。免疫化学检测到的膜相关CA IV在患者和正常对照中大小相同，但患者的带强度比正常对照小得多。可溶性CA IV在患者体内明显升高。这些结果提示CA - IV在肾膜上的锚定机制可能是异常的，是肾近端小管酸中毒的病因。同时检测尿膜部分碱性磷酸酶，与ca4一样通过糖基磷脂酰肌醇锚定在膜上，结果正常。我们推测CA - IV基因特别是c端结构域的微小突变可能是导致该疾病的原因。我们根据内含子序列构建了7组PCR引物，扩增出CA IV基因的7个外显子，并以PCR引物作为序列引物进行测序。外显子-内含子边界和外显子未检测到突变。我们得出结论，CA IV突变不太可能发生在患者身上。患者持续的，纯粹的近端肾小管酸中毒的原因仍有待阐明。