Laforenza U, Patrini C, Gastaldi G, Rindi G
Institute of Human Physiology, University of Pavia, Italy.
Alcohol Alcohol. 1990;25(6):591-603. doi: 10.1093/oxfordjournals.alcalc.a045055.
The effect of ethanol (4.7 g/kg body wt intragastrically as a single dose or once daily for 35 days) on the levels of the thiamine metabolizing enzymes (thiamine pyrophosphokinase, TPKase; thiamine pyrophosphatase, TPPase; and monophosphatase, TMPase) was studied in different organs (liver, kidney, small intestine, heart and skeletal muscle) and nervous regions (cerebral cortex, cerebellum, medulla oblongata, pons, corpus callosum, hypothalamus and sciatic nerve) of the rat. In order to evaluate the non-specific effects of the stress of gastric gavage and of the additional caloric intake, appropriate control groups of animals were treated intragastrically with water or with a saccharose solution isoenergetic with ethanol respectively. All animals were reared on a nutritionally adequate diet supplying amounts of thiamine higher than the recommended daily requirement. Enzymatic activities were determined quantitatively by biochemical methods. Tissue TPKase levels were generally reduced by both acute and chronic ethanol administration. TPPase levels were generally reduced after acute and increased after chronic ethanol treatment. Changes in brain TMPase levels were similar to those observed for TPPase. In visceral organs and skeletal muscle TMPase activity was increased by chronic ethanol treatment as compared to acute ethanol administration. In conclusion, ethanol exerts a marked influence on the tissue levels of the thiamine metabolizing enzymes: the activity of the enzymes dephosphorylating thiamine phosphates is increased whereas the activity of the thiamine pyrophosphate synthesizing enzyme is reduced. These changes may contribute to an important extent to the disturbances in thiamine cellular uptake and metabolism observed in alcoholism.
研究了乙醇（单剂量灌胃4.7 g/kg体重或每日一次，连续35天）对大鼠不同器官（肝脏、肾脏、小肠、心脏和骨骼肌）及神经区域（大脑皮层、小脑、延髓、脑桥、胼胝体、下丘脑和坐骨神经）中硫胺素代谢酶（硫胺素焦磷酸激酶，TPKase；硫胺素焦磷酸酶，TPPase；和单磷酸酶，TMPase）水平的影响。为了评估灌胃应激及额外热量摄入的非特异性影响，分别设置了合适的对照组动物，一组经胃给予水，另一组经胃给予与乙醇能量相当的蔗糖溶液。所有动物均饲养于营养充足的饮食环境中，所供应的硫胺素量高于推荐的每日需求量。采用生化方法定量测定酶活性。急性和慢性乙醇给药通常都会降低组织TPKase水平。急性乙醇处理后TPPase水平通常降低，而慢性乙醇处理后则升高。脑TMPase水平的变化与TPPase相似。与急性乙醇给药相比，慢性乙醇处理使内脏器官和骨骼肌中的TMPase活性增加。总之，乙醇对硫胺素代谢酶的组织水平有显著影响：使硫胺素磷酸脱磷酸化的酶活性增加，而硫胺素焦磷酸合成酶的活性降低。这些变化在很大程度上可能导致了酒精中毒时硫胺素细胞摄取和代谢的紊乱。
