title: Acute hypoxia upregulates NOS gene expression in rats.
abstract: This study aimed to investigate the influence of acute tissue hypoxygenation on the expression of NO synthase (NOS) genes in vivo. To this end, male Sprague-Dawley rats were exposed either to 9% oxygen or to 0.1% carbon monoxide for 6 h, and mRNA levels of NOS-I, -II, and -III in kidneys, livers, lungs, and left and right heart ventricles were assayed by ribonuclease protection. For comparison, mRNA levels of erythropoietin were also measured in these tissues. NOS-III mRNA was highly abundant in all organs investigated. NOS-II mRNA was detected in lungs and hearts but not in kidneys and livers. NOS-I mRNA was found in kidneys, lungs, and hearts but not in livers. NOS-III mRNA levels were upregulated by hypoxia in all tissues examined, with the least effect (1.2-fold) in the left ventricle and the greatest effect (2.6-fold) in the lung. NOS-II mRNA was substantially downregulated in the ventricles by both treatments but not changed in the lung. NOS-I mRNA was upregulated by carbon monoxide in kidneys and lungs and by 9% oxygen in the lung. These findings suggest that NOS-III and possibly also NOS-I gene expression behave like oxygen-regulated genes, whereas the general effect of tissue hypoxygenation on NOS-II gene expression is less clear. Because NOS-III is primarily expressed in endothelial cells, a general upregulation of NOS in these cells may be of relevance for the regulation and maintenance of blood flow through hypoxic tissues.
authors.affiliation: Institut für Physiologie, Universität Regensburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Gess
authors.forename: K
authors.initials: K
authors.lastname: Schricker
authors.forename: M
authors.initials: M
authors.lastname: Pfeifer
authors.forename: A
authors.initials: A
authors.lastname: Kurtz
mesh_terms: D000199:Actins / Q000096:biosynthesis; D000818:Animals; D002248:Carbon Monoxide / Q000494:pharmacology; D004921:Erythropoietin / Q000096:biosynthesis; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D000860:Hypoxia / Q000201:enzymology*; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008297:Male; D009206:Myocardium / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D009928:Organ Specificity; D010100:Oxygen / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic
chemical_list: D000199:Actins; D012333:RNA, Messenger; D004921:Erythropoietin; D002248:Carbon Monoxide; D019001:Nitric Oxide Synthase; D010100:Oxygen