色氨酸及色氨酸吡咯酶在血红素调节中的作用。脂解作用以及血清蛋白结合色氨酸的直接置换在给予内毒素、吗啡、棕榈酸酯、水杨酸盐及茶碱对大鼠肝脏5-氨基酮戊酸合酶活性和色氨酸吡咯酶血红素饱和度的相反作用中的作用。

Tryptophan and tryptophan pyrrolase in haem regulation. The role of lipolysis and direct displacement of serum-protein-bound tryptophan in the opposite effects of administration of endotoxin, morphine, palmitate, salicylate and theophylline on rat liver 5-aminolaevulinate synthase activity and the haem saturation of tryptophan pyrrolase.

作者信息

Badawy A A, Morgan C J

出版信息

Biochem J. 1982 Sep 15;206(3):451-60. doi: 10.1042/bj2060451.

DOI:10.1042/bj2060451

PMID:7150256

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1158610/

Abstract

The increase in the haem saturation of rat liver tryptophan pyrrolase caused by tryptophan administration was previously shown to be associated with a decrease in 5-aminolaevulinate synthase activity. 2. It is now shown that similar reciprocal effects are caused by palmitate and salicylate, both of which increase tryptophan availability to the liver by direct displacement of the serum-protein-bound amino acid. 3. The reciprocal effects on the former two parameters caused by endotoxin and morphine are associated with an increase in liver tryptophan concentration produced by a lipolysis-dependent, non-esterified fatty acid-mediated, displacement of the serum-protein-bound amino acid. 4. All these changes and those caused by another lipolytic agent, theophylline, are prevented by the beta-adrenoceptor-blocking agent propranolol and by the opiate-receptor antagonist naloxone, whose anti-lipolytic nature is demonstrated. 5. High correlation coefficients have been obtained for one or more pairs of the following parameters: serum non-esterified fatty acid concentration, free serum tryptophan concentration, liver tryptophan concentration, liver 5-aminolaevulinate synthase activity, liver holo-(tryptophan pyrrolase) activity and the haem saturation of liver tryptophan pyrrolase. 6. It is suggested that liver tryptophan concentration may play an important role in the regulation of 5-aminolaevulinate synthase synthesis, and that the latter may be subject to control by changes in lipid metabolism and may be influenced by pharmacological agents that affect tryptophan disposition. 7. Preliminary evidence suggests that tryptophan may be bound in the liver and that such a possible binding may control its availability for its hepatic functions.

摘要

先前已表明，色氨酸给药导致大鼠肝脏色氨酸吡咯酶的血红素饱和度增加与5-氨基酮戊酸合酶活性降低有关。2. 现在表明，棕榈酸酯和水杨酸盐也会产生类似的相互作用，二者均通过直接置换血清蛋白结合氨基酸来增加肝脏对色氨酸的摄取。3. 内毒素和吗啡对前两个参数的相互作用与肝脏色氨酸浓度增加有关，这种增加是由脂解依赖性、非酯化脂肪酸介导的血清蛋白结合氨基酸置换所引起的。4. 所有这些变化以及另一种脂解剂茶碱所引起的变化，均被β-肾上腺素受体阻滞剂普萘洛尔和阿片受体拮抗剂纳洛酮所阻断，这证明了它们的抗脂解性质。5. 以下参数中的一对或多对参数之间获得了高相关系数：血清非酯化脂肪酸浓度、游离血清色氨酸浓度、肝脏色氨酸浓度、肝脏5-氨基酮戊酸合酶活性、肝脏全（色氨酸吡咯酶）活性以及肝脏色氨酸吡咯酶的血红素饱和度。6. 有人提出，肝脏色氨酸浓度可能在5-氨基酮戊酸合酶合成的调节中起重要作用，并且后者可能受脂质代谢变化的控制，还可能受到影响色氨酸处置的药物的影响。7. 初步证据表明，色氨酸可能在肝脏中被结合，这种可能的结合可能控制其用于肝脏功能的可用性。