Blachier F, Mignon A, Soubrane O
Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
Nitric Oxide. 1997 Jun;1(3):268-72. doi: 10.1006/niox.1997.0127.
Liver cells can produce nitric oxide from L-arginine through either constitutive NO synthase or inducible NO synthase (NOS) detected after in vivo or in vitro treatment with cytokines and/or lipopolysaccharide (LPS). The effects of NO on liver cells are associated with protein synthesis and mitochondrial electron transfer inhibition. L-Arginine is also the precursor of L-ornithine and polyamines. The latter are considered to be protective in the liver in several experimental models. The aim of the present work was to test the effects of polyamines on LPS-inducible NOS activity in rat liver cytosol using the test of radioactive L-citrulline synthesis from L-[guanido-14C]arginine. The three polyamines inhibited inducible NO synthase activity with the following hierarchy: spermine > spermidine approximately equal to putrescine. The 0.5 mM spermine was found to inhibit 50% of inducible NO synthase activity. The present data suggest an inhibitory interrelationship in the liver between two metabolites derived from the common precursor L-arginine.
肝细胞可通过组成型一氧化氮合酶或诱导型一氧化氮合酶（NOS）从L-精氨酸产生一氧化氮，后者可在体内或体外经细胞因子和/或脂多糖（LPS）处理后检测到。一氧化氮对肝细胞的影响与蛋白质合成和线粒体电子传递抑制有关。L-精氨酸也是L-鸟氨酸和多胺的前体。在几个实验模型中，后者被认为对肝脏具有保护作用。本研究的目的是使用从L-[胍基-14C]精氨酸合成放射性L-瓜氨酸的试验，测试多胺对大鼠肝细胞溶质中LPS诱导的NOS活性的影响。三种多胺抑制诱导型一氧化氮合酶活性的顺序如下：精胺>亚精胺≈腐胺。发现0.5 mM精胺可抑制50%的诱导型一氧化氮合酶活性。目前的数据表明，在肝脏中，源自共同前体L-精氨酸的两种代谢物之间存在抑制性相互关系。
