Regulation of cyclooxygenase-2 in renal medulla.
Renal medulla is a major site for production and action of prostaglandins (PGs). The renal medullary functions as well as structural integrity are in part dependent on PGs under certain physiological or pathophysiological conditions. The two COX isoforms, COX-1 (constitutive form) and COX-2 (inducible form) are both abundantly expressed in renal inner medulla at basal state, raising a question of which COX isoform may mediate the known functions of PGs in the region. As in many other cell types, COX-1 expression in renal medulla is unlikely subject to robust regulation. In contrast, COX-2 expression in renal medulla is markedly stimulated by chronic salt loading, dehydration and endotoxaemia in vivo. At cellular levels, the signalling pathways responsible for the COX-2 stimulation in renal medullary cells seem to involve both the mitogen-activated protein kinases and NF-kappa B. It is likely that in response to various insults that are detrimental to renal medulla, the induction of PG synthesis may become more dependent on COX-2 than COX-1, and this phenomenon may be relevant to the cytoprotective response against the insults.
Yang
T
T
National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
D000818:Animals; D051546:Cyclooxygenase 2; D019332:Endothelin-1 / Q000378:metabolism; D016166:Free Radical Scavengers / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D007679:Kidney Medulla / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011453:Prostaglandins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D012492:Salts / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D051193:Toll-Like Receptors; D014868:Water Deprivation / Q000502:physiology
D019332:Endothelin-1; D016166:Free Radical Scavengers; D007527:Isoenzymes; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011453:Prostaglandins; D011956:Receptors, Cell Surface; D012492:Salts; D051193:Toll-Like Receptors; D009569:Nitric Oxide; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases