Wada E
Arch Biochem Biophys. 1986 Nov 15;251(1):215-21. doi: 10.1016/0003-9861(86)90068-8.
An accumulation of galactose-1,4-lactone, an oxidation product of galactose, was observed in various tissues of galactosemic guinea pigs fed a 40% galactose diet for 6 weeks. In addition, an accumulation of the two galactose metabolites varied among organs. The highest content of the lactone was observed in the liver and the content of the lactone exceeded that of the reduced counterpart. The lens gave the highest galactitol content. In the serum the level of the lactone was very low. A trace amount of the lactone was detected in the kidney while it was mostly excreted into urine within 54 h upon withdrawal of the diet. On the other hand, in the animals kept on a high galactose diet for only 2 days, urinary lactone rapidly decreased. These observations indicated that a high galactose level in the circulation was associated with the production of the lactone in various tissues and that the accumulated lactone was released into the circulation very slowly and then excreted into the urine. Suppression of galactitol production by administration of an aldose reductase inhibitor resulted in the accumulation of the lactone in the lens, the testis, and the muscle, as well as in the circulation. The lactone thus produced was excreted exclusively into the urine. This observation indicates a close relationship between the oxidative and reductive metabolisms of galactose at a toxic level.
在喂食40%半乳糖饮食6周的半乳糖血症豚鼠的各种组织中，观察到半乳糖的氧化产物半乳糖-1,4-内酯的积累。此外，两种半乳糖代谢物的积累在不同器官中有所不同。内酯含量最高的是肝脏，且内酯含量超过了其还原对应物的含量。晶状体中半乳糖醇含量最高。血清中内酯水平非常低。在肾脏中检测到微量内酯，而在停止饮食后54小时内，它大多会排泄到尿液中。另一方面，在仅喂食高半乳糖饮食2天的动物中，尿内酯迅速减少。这些观察结果表明，循环中高半乳糖水平与各种组织中内酯的产生有关，并且积累的内酯非常缓慢地释放到循环中，然后排泄到尿液中。通过给予醛糖还原酶抑制剂抑制半乳糖醇的产生，导致内酯在晶状体、睾丸和肌肉以及循环中积累。由此产生的内酯仅排泄到尿液中。这一观察结果表明，在有毒水平下半乳糖的氧化代谢和还原代谢之间存在密切关系。
