title: Cytochrome c oxidase expression in chronic and intermittent hypoxia rat gastrocnemius muscle quantitated by CE.
abstract: We investigated the effects of hypoxia and intermittent hypoxia in rat muscle by quantitating the expression of genes encoding cytochrome c oxidase (CytOx) subunits I, II and IV, and ribosomal 12S RNA. The quantitative assessment was made by CE in a polymer network, laser being used to facilitate the detection of induced fluorescence. Constant and intermittent hypoxia influence gene expression and ribosomal activity to different degrees. We found constant hypoxia to be accompanied by an increment in the mitochondrial CytOx subunit transcripts II and I and 12S ribosomal subunit, whereas the nuclear subunit (IV) remained unchanged. No changes were observed in intermittent hypoxic rats. Despite the increment in messenger expression, the decrease in enzyme activity was accompanied by a decrease in citrate synthase activity, a marker of mitochondrial function. The increment in CytOx mitochondrial subunits messengers and ribosomal 12S RNA under prolonged chronic hypoxia could be a consequence of reduced protein synthesis that leads to messenger accumulation.
authors.affiliation: Institute of Molecular Bioimaging and Physiology, CNR Segrate Milano, Milano, Italy.
authors.forename: Marilena
authors.initials: M
authors.lastname: Ripamonti
authors.forename: Agnese
authors.initials: A
authors.lastname: Viganò
authors.forename: Manuela
authors.initials: M
authors.lastname: Moriggi
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Milano
authors.forename: Ludwig K
authors.initials: LK
authors.lastname: von Segesser
authors.forename: Michele
authors.initials: M
authors.lastname: Samaja
authors.forename: Cecilia
authors.initials: C
authors.lastname: Gelfi
mesh_terms: D000818:Animals; D003576:Electron Transport Complex IV / Q000235:genetics*; D019075:Electrophoresis, Capillary / Q000379:methods*; D015971:Gene Expression Regulation, Enzymologic; D000860:Hypoxia / Q000201:enzymology* / Q000235:genetics; D007834:Lasers; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D018482:Muscle, Skeletal / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013050:Spectrometry, Fluorescence
chemical_list: D012333:RNA, Messenger; D003576:Electron Transport Complex IV