Hoshi A, Takahashi M, Fujii J, Myint T, Kaneto H, Suzuki K, Yamasaki Y, Kamada T, Taniguchi N
Department of Biochemistry, Osaka University Medical School, Japan.
Biochem J. 1996 Aug 15;318 ( Pt 1)(Pt 1):119-23. doi: 10.1042/bj3180119.
Sorbitol dehydrogenase (SDH) is involved in the polyol pathway, which plays an important role in the pathogenesis of diabetic complications. We have measured the tissue distributions of SDH mRNA, both the immunoreactive enzyme levels and the enzyme activity. SDH mRNA was especially abundant in liver, kidney and testis. Both the activity and enzyme content are high in liver and kidney but not in testis. The discrepancy between mRNA and immunoreactive enzyme levels and the activity of SDH observed in testis was also seen in livers of streptozotocin-induced diabetic rats. SDH was found to exist in both glycated and non-glycated forms, with larger amounts of the glycated protein in the diabetic liver. Moreover, after incubation of purified enzyme with glucose or fructose, its activity was markedly decreased. These results indicate that glycation causes a decrease in SDH activity in liver under diabetic conditions. The same post-transcriptional event might occur to decrease the activity of SDH in testis in normal animals.
山梨醇脱氢酶（SDH）参与多元醇途径，该途径在糖尿病并发症的发病机制中起重要作用。我们测定了SDH mRNA的组织分布、免疫反应性酶水平和酶活性。SDH mRNA在肝脏、肾脏和睾丸中特别丰富。肝脏和肾脏中的活性和酶含量都很高，但睾丸中则不然。在链脲佐菌素诱导的糖尿病大鼠的肝脏中也观察到睾丸中SDH mRNA与免疫反应性酶水平和活性之间的差异。发现SDH以糖化和非糖化两种形式存在，糖尿病肝脏中糖化蛋白的含量更高。此外，将纯化的酶与葡萄糖或果糖孵育后，其活性明显降低。这些结果表明，在糖尿病条件下，糖基化会导致肝脏中SDH活性降低。在正常动物的睾丸中，可能会发生相同的转录后事件以降低SDH的活性。
