Regulation of the genes for arginase isoforms and related enzymes in mouse macrophages by lipopolysaccharide. Am J Physiol 277:E110–E117

for arginase isoforms and related enzymes in mouse macro-phages by lipopolysaccharide. Am. J. Physiol. 277 (Endocri-nol. 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 macrophages and rat tissues in vivo by bacterial lipopolysac-charide (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 was studied in mouse tissues in vivo and in perito-neal macrophages with RNA blot and immunoblot analyses and enzyme assay. When mice were injected intraperitoneally with LPS, inducible nitric oxide synthase (iNOS) and argi-nase II were induced early in the lung and spleen. mRNAs for argininosuccinate synthase (AS) and ornithine decarboxylas