Glucagon stimulation of phenylalanine metabolism. The effects of acute and chronic glucagon treatment.
Glucagon stimulation of phenylalanine metabolism. The effects of acute and chronic glucagon treatment.
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胰高血糖素刺激苯丙氨酸代谢。
DOI：
10.1016/0026-0495(82)90089-0
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
Harper,AE
中科院分区：
文献类型：
--
作者：
Haley,CJ;Harper,AE
研究了急性和慢性胰高血糖素治疗对大鼠体内苯丙氨酸代谢的影响。单次大剂量胰高血糖素（2 mg/kg，i. p.）通过羟基化和转氨作用增加了大量苯丙氨酸（1.27 g/kg）的代谢。代谢增加与肝苯丙氨酸：丙酮酸转氨酶，酪氨酸转氨酶和苯丙氨酸羟化酶的活性增加有关。在给予该量苯丙氨酸的大鼠中，对羟基苯丙酮酸双加氧酶反应明显具有速率限制性，如除了苯丙酮酸和苯乳酸的尿排泄外，对羟基苯丙酮酸和对羟基苯乳酸的尿排泄增加所示。长期胰高血糖素治疗（1.25 mg/kg，每12小时一次，持续8天）增加了苯丙氨酸负荷的氧化和苯丙酮酸和苯乳酸的尿排泄，但对羟基苯丙酮酸或对羟基苯乳酸没有增加。苯丙酮酸和苯乳酸排泄增加与肝苯丙氨酸：丙酮酸转氨酶活性增加相关。尿液中不存在对羟基苯丙酮酸和苯丙氨酸氧化增加意味着，在长期给予胰高血糖素的大鼠中，通过对羟基苯丙酮酸双加氧酶反应的对羟基苯丙酮酸通量增加。本文报道了一种基于耗氧量测定的苯丙氨酸羟化酶动力学分析法。
The effects of acute and chronic glucagon treatment on phenylalanine metabolism in vivo in the rat have been investigated. A single, large dose of glucagon (2 mg/kg, i.p.) increased metabolism of a large load of phenylalanine (1.27 g/kg) via hydroxylation and transmination. The increased metabolism was associated with increased activities of hepatic phenylaalnine:pyruvate aminotransferase, tyrosine aminotransferase and phenylalanine hydroxylase. In rats administered this amount of phenylalanine, the p-hydroxyphenylpyruvate dioxygenase reaction was apparently rate limiting, as indicated by increased urinary excretion of p-hydroxyphenylpyruvate and p-hydroxyphenyllactate, in addition to urinary excretion of phenylpyruvate and phenyllactate. Chronic glucagon treatment (1.25 mg/kg every 12 hr for 8 days) increased oxidation of the large phenylalanine load and urinary excretion of phenylpyruvate and phenyllactate but not p-hydroxyphenylpyruvate or p-hydroxyphenyllactate. The increased excretion of phenylpyruvate and phenyllactate was associated with an increase in hepatic phenylalanine: pyruvate aminotransferase activity. The absence of p-hydroxyphenylpyruvate in the urine and the increased oxidation of phenylalanine imply that, in rats administered glucagon chronically, flux of p-hydroxyphenylpyruvate through the p-hydroxyphenylpyruvate dioxygenase reaction was increased. A kinetic assay for phenylalanine hydroxylase based on measurement of oxygen consumption is described.