Localization of the Human Gene for Inducible Nitric Oxide Synthase (NOS2) to Chromosome 17q11.2-q12

Nitric oxide (NO) is a simple molecule implicated in neuronal transmission, endothelium-dependent vasodilatation, and macrophage immunologic activation. Enzymes responsible for NO synthesis constitute a family with at least three distinct isoforms - neuronal (NOS1), endothelial (NOS3), and inducible tissue. NO synthase enzymatic activity is constitutively expressed but activation of the calcium/calmodulin signaling pathway is required for maximal activity. Constitutive NO synthases contrast with a pathway for NO synthesis evident in macrophages, Kupffer cells, hepatocytes, vascular smooth muscle, and mesangial cells, among others. NO synthase activity is induced in these cell types by cytokines or bacterial wall products over a period of many hours. 14 refs., 1 fig.