Agmatine biosynthesis by arginine decarboxylation is well-positioned to compete with the principal arginine-dependent pathways, namely: nitrogen metabolism (urea cycle), and polyamine and nitric oxide (NO) synthesis (see illustration Agmatine Metabolic Pathways). Agmatine degradation occurs mainly by hydrolysis, catalyzed by agmatinase into urea and putrescine, the diamine precursor of polyamine biosynthesis. An alternative pathway, mainly in peripheral tissues, is by diamine oxidase-catalyzed oxidation into agmatine-aldehyde, which is in turn converted by aldehyde dehydrogenase into guanidinobutyrate and secreted by the kidneys.