Gabriella M G, Palatroni P
Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy.
Histochem J. 1992 Jan;24(1):51-8. doi: 10.1007/BF01043287.
The effects of different concentrations of acetazolamide, a specific carbonic anhydrase inhibitor, have been investigated in the quail kidney. The histochemical patterns, interpreted by means of quantitative analyses proved that 0.1 microM acetazolamide inhibited the enzyme activity in all the reactive tubular segments except for distal tubules. At this site, the reaction product disappeared from the cytoplasm but strong positivity persisted at the apical surface. The luminal staining was still present at higher inhibitor concentrations up to 0.8 microM acetazolamide. Under histophotometric analyses, the residual reactivity proved to be nearly the same at the increasing inhibitor concentrations assayed. The validity of the results was checked by similar investigations in other control tissues. On the basis of the properties known for carbonic anhydrase in mammalian kidney, we conclude that the luminal membrane staining in the quail distal tubules might be due to a carbonic anhydrase isoenzyme that is similar, both in affinity for acetazolamide and in intracellular localization, to the membrane-bound enzyme purified from mammalian proximal convoluted tubules.
在鹌鹑肾脏中研究了特定碳酸酐酶抑制剂不同浓度的乙酰唑胺的作用。通过定量分析解释的组织化学模式证明，0.1微摩尔乙酰唑胺抑制了除远端小管外所有反应性肾小管节段中的酶活性。在此部位，反应产物从细胞质中消失，但顶端表面仍保持强阳性。在高达0.8微摩尔乙酰唑胺的较高抑制剂浓度下，管腔染色仍然存在。在组织光度分析中，在所测定的抑制剂浓度增加时，残余反应性证明几乎相同。通过在其他对照组织中的类似研究检查了结果的有效性。根据哺乳动物肾脏中碳酸酐酶的已知特性，我们得出结论，鹌鹑远端小管中的管腔膜染色可能是由于一种碳酸酐酶同工酶，其对乙酰唑胺的亲和力和细胞内定位与从哺乳动物近端曲管纯化的膜结合酶相似。
