饥饿
糖异生
内科学
内分泌学
酪氨酸
内脏的
新陈代谢
苯丙氨酸
氨基酸
体内
蛋白质周转
生物
蛋白质代谢
生物化学
化学
蛋白质生物合成
医学
血流
生物技术
作者
Ivo de Blaauw,N.E.P. Deutz,M.F. von Meyenfeldt
出处
期刊:American Journal of Physiology-gastrointestinal and Liver Physiology
[American Physiological Society]
日期:1996-02-01
卷期号:270 (2): G298-G306
被引量:11
标识
DOI:10.1152/ajpgi.1996.270.2.g298
摘要
During starvation, splanchnic organs are proportionally more affected by protein loss than other organs. Amino acid membrane transport is one of the regulating mechanisms of protein turnover, but until now in vivo data were lacking. To study in vivo phenylalanine and tyrosine membrane transport and protein turnover in splanchnic organs, a primed continuous infusion of L-[2,6-3H]phenylalanine was given to control rats (postabsorptive) and after short (40 h) and prolonged (112 h) starvation. Data were analyzed using a three-compartment model previously used in muscle membrane transport studies. Inward and outward amino acid plasma-tissue membrane transport rates in both the liver and gut were upregulated after prolonged starvation. Metabolic shunting of phenylalanine and tyrosine increased in the gut but decreased to zero in the liver after prolonged starvation. In conjunction with this, gut and liver protein turnover increased after prolonged starvation. In the liver the net uptake of gluconeogenic precursors also increased, indicative for increased gluconeogenesis. The observed changes in amino acid metabolism in both splanchnic organs after prolonged starvation may reflect an adaptation of the gut and liver to nutritional deprivation and could be of benefit during refeeding.
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