Abe T, Itokawa Y
Int J Vitam Nutr Res. 1977;47(4):307-14.
To clarify the effect of ethanol on thiamine metabolism and activity of transketolase, a thiamine dependent enzyme, in vivo and in vitro experiments were carried out. For the in vivo experiment, rats were separated into four groups: Group 1, thiamine sufficient diet with no ethanol administered; group 2, thiamine sufficient diet and ethanol administered by stomach tube; group 3, thiamine deficient diet with no ethanol administered; group 4, thiamine deficient diet and ethanol administered. After three weeks, the rats were killed, then thiamine levels and the activity of transketolase were assayed. Thiamine concentration in brains and livers of ethanol fed rats were lower than that in control rats. Urinary thiamine was higher in ethanol administered rats than in controls. The increase in the liver transketolase activity by the in vitro addition of cocarboxylase (TPP effect) was higher in group 3 than in group 4 although original transketolase activity was lower in group 4. For the in vitro experiment, various amounts of ethanol or acetaldehyde were added to the supernatant of brain and liver of intact rats, and transketolase activity was determined. Inhibition by acetaldehyde to transketolas was about 10 times higher than that by ethanol.
为阐明乙醇对硫胺素代谢及转酮醇酶（一种依赖硫胺素的酶）活性的影响，进行了体内和体外实验。在体内实验中，将大鼠分为四组：第1组，给予硫胺素充足的饮食且不给予乙醇；第2组，给予硫胺素充足的饮食并通过胃管给予乙醇；第3组，给予硫胺素缺乏的饮食且不给予乙醇；第4组，给予硫胺素缺乏的饮食并给予乙醇。三周后，处死大鼠，然后测定硫胺素水平和转酮醇酶活性。给予乙醇的大鼠脑和肝脏中的硫胺素浓度低于对照大鼠。给予乙醇的大鼠尿中硫胺素高于对照组。尽管第4组的原始转酮醇酶活性较低，但第3组通过体外添加羧化辅酶（TPP效应）使肝脏转酮醇酶活性的增加高于第4组。在体外实验中，向完整大鼠的脑和肝脏上清液中加入不同量的乙醇或乙醛，并测定转酮醇酶活性。乙醛对转酮醇酶的抑制作用比乙醇高约10倍。
