background: during the initial phase of an infection, there is an upregulation of inducible nitric oxide synthase in the macrophages for the production of nitric oxide. this is followed by the recruitment of polymorphonuclear leukocytes (neutrophils) which release arginase. arginase competes with inducible nitric oxide synthase for a common substrate l-arginine. objective: to investigate whethe...

Mammals express two isoforms of arginase, designated types I and II. Arginase I is a component of the urea cycle, and inherited defects in arginase I have deleterious consequences in humans. In contrast, the physiologic role of arginase II has not been defined, and no deficiencies in arginase II have been identified in humans. Mice with a disruption in the arginase II gene were created to inves...

Activated macrophages avidly consume arginine via the action of inducible nitric oxide synthase (iNOS) and/or arginase. In contrast to our knowledge regarding macrophage iNOS expression, the stimuli and mechanisms that regulate expression of the cytosolic type I (arginase I) or mitochondrial type II (arginase II) isoforms of arginase in macrophages are poorly defined. We show that one or both a...

Arginase, which exists as the isoforms arginase I and II, catalyzes the hydrolysis of arginine to ornithine and urea. Ornithine is the principal precursor for production of polyamines, which are required for cell proliferation. Rat aortic smooth muscle cells (RASMC) contain constitutive arginase I, and arginase inhibitors cause inhibition of cell proliferation. The objective of this study was t...

Activated murine macrophages metabolize arginine by two alternative pathways involving the enzymes inducible NO synthase (iNOS) or arginase. The balance between the two enzymes is competitively regulated by Th1 and Th2 T helper cells via their secreted cytokines: Th1 cells induce iNOS, whereas Th2 cells induce arginase. Whereas the role of macrophages expressing iNOS as inflammatory cells is we...

Arginase regulates arginine metabolism, ornithine-urea cycle, and immunological surveillance. Arginase-I is predominant in cytosol, and arginase-II is localised in the mitochondria. A mitochondrial membrane-bound arginase has also been proposed to be adsorbed with outer membrane of mitochondria which gets released by 150 mM potassium chloride (KCl). It is presumed that inclusion of 150 mM KCl i...

Salimuddin,Akitoshi Nagasaki, Tomomi Gotoh, Hirotaka Isobe, and Masataka Mori. Regulation of the genes for arginase isoforms and related enzymes in mouse macrophages by lipopolysaccharide. Am. J. Physiol. 277 (Endocrinol. Metab. 40): E110–E117, 1999.—Arginase exists in two isoforms, the hepatic (arginase I) and extrahepatic types (arginase II). Arginase I is markedly induced in rat peritoneal m...

Oxidized low-density lipoprotein (OxLDL) impairs NO signaling and endothelial function, and contributes to the pathogenesis of atherosclerosis. Arginase reciprocally regulates NO levels in endothelial cells by competing with NO synthase for the substrate l-arginine. In human aortic endothelial cells, OxLDL stimulation increased arginase enzyme activity in a time- and dose-dependent manner. Argi...

Arginase exists in two isoforms, the hepatic (arginase I) and extrahepatic types (arginase II). Arginase I is markedly induced in rat peritoneal macrophages and rat tissues in vivo by bacterial lipopolysaccharide (LPS). In contrast, both arginase I and arginase II are induced in LPS-activated mouse peritoneal macrophages. In the present study, expression of arginase isoforms and related enzymes...