Escrivá F, Pascual-Leone A M, Galán A, Encinas J P
Rev Esp Fisiol. 1983 Dec;39(4):363-71.
The neo-T4 syndrome was induced by subcutaneous administration of a total dose of (150 micrograms) L-thyroxine (T4) to rats from their first day of live. Neo-T4 animals and their controls were sacrificed at 2, 4, 8, 11, 14, 22 and 25 days of age. A decrease in body weight was observed from the second day of life, and a decrease in brain weight from the eighth day of life in the neo-T4 animals. Blood glucose and plasma insulin levels were decreased from 2nd day through 22nd day of life. Total plasma ketone bodies and beta-OH butyrate levels increased in the neo-T4 animals with respect to controls. until 8th day, although acetoacetate increased only until 4th day. The activity of key enzymes in the ketone bodies utilization pathway (3-hydroxybutyrate dehydrogenase, 3-oxoacid CoA-transferase and acetoacetyl-CoA thiolase) were also measured in the animals brain. We found an activation of 3-hydroxybutyrate dehydrogenase until 11th day and 3-oxoacid CoA-transferase until 14th day, but no change in acetoacetyl CoA-thiolase was observed. Ketone bodies play a key role as energy substrates and precursors of brain lipids during the period of intense growth and myelination of the CNS. Considering the alterations described in this paper it seems that neo-T4 syndrome could be an interesting model for studying metabolism of those substances in brain.
从出生第一天起,给大鼠皮下注射总剂量为150微克的L-甲状腺素(T4),从而诱导产生新T4综合征。新T4动物及其对照在2、4、8、11、14、22和25日龄时被处死。在新T4动物中,从出生第二天起观察到体重下降,从出生第八天起观察到脑重下降。从出生第二天到第22天,血糖和血浆胰岛素水平下降。与对照组相比,新T4动物的血浆总酮体和β-羟基丁酸水平升高。直到第8天,尽管乙酰乙酸仅在第4天之前升高。还测量了动物脑中酮体利用途径中的关键酶(3-羟基丁酸脱氢酶、3-氧代酸辅酶A转移酶和乙酰乙酰辅酶A硫解酶)的活性。我们发现3-羟基丁酸脱氢酶在第11天之前被激活,3-氧代酸辅酶A转移酶在第14天之前被激活,但未观察到乙酰乙酰辅酶A硫解酶有变化。在中枢神经系统强烈生长和髓鞘形成期间,酮体作为能量底物和脑脂质前体发挥关键作用。考虑到本文所述的变化,新T4综合征似乎可能是研究脑中这些物质代谢的一个有趣模型。