Zopf Steffen, Flämig Jakob, Schmid Heide, Miosge Nicolai, Blaschke Sabine, Hahn Eckhart G, Müller Gerhard A, Grunewald Rolf W
Department of Internal Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany.
Histol Histopathol. 2009 Apr;24(4):447-55. doi: 10.14670/HH-24.447.
Sorbitol plays an important role in the osmotic regulation of the mammalian kidney. Sorbitol synthesis is regulated by the enzyme aldose reductase (AR) and its degradation to fructose is catalyzed by the enzyme sorbitol dehydrogenase (SDH). Various data exist on the polyol pathway on the rat kidney, but little is known about the distribution of the polyol pathway enzymes in the human kidney. Determination of enzyme activities and a semiquantitative determination of mRNA expression, immunohistochemistry and in-situ hybridisation in healthy human kidney tissue was carried out. The enzyme activity of AR showed a fourfold increase from cortex to papilla, while SDH-activity dropped from cortex to papilla by a factor of four. Corresponding data was obtained at the mRNA level from the semiquantitative polymerase chain reaction (PCR). Additional differentiation at the cellular level reveals both enzymes in cells of the proximal and distal tubules, thick ascending loop, thin loop and collecting duct. Studies of enzyme activity and expression by immunohistochemistry, PCR and in-situ hybridization presented corresponding results with respect to the localization of the enzymes, which match the experimental data obtained from rats very well. Thus, the established rat model might well represent the situation in the human kidney, too.
山梨醇在哺乳动物肾脏的渗透调节中起重要作用。山梨醇的合成由醛糖还原酶（AR）调节，其降解为果糖则由山梨醇脱氢酶（SDH）催化。关于大鼠肾脏中多元醇途径已有各种数据，但对于人肾脏中多元醇途径酶的分布了解甚少。本研究对健康人肾组织进行了酶活性测定、mRNA表达的半定量测定、免疫组织化学和原位杂交。AR的酶活性从皮质到乳头增加了四倍，而SDH活性从皮质到乳头下降了四倍。通过半定量聚合酶链反应（PCR）在mRNA水平获得了相应数据。在细胞水平上的进一步分化显示，近端和远端小管、厚升支、细段和集合管的细胞中均有这两种酶。通过免疫组织化学、PCR和原位杂交对酶活性和表达的研究，在酶的定位方面呈现了相应结果，与从大鼠获得的实验数据非常吻合。因此，已建立的大鼠模型很可能也代表了人肾脏的情况。
