title: Oxidative phosphorylation and its coupling to mitochondrial creatine and adenylate kinases in human gastric mucosa.
abstract: Energy metabolism in gastrobiopsy specimens of the antral and corpus mucosa, treated with saponin to permeabilize the cells, was studied in patients with gastric diseases. The results show twice lower oxidative capacity in the antral mucosa than in the corpus mucosa and the relative deficiency of antral mitochondria in complex I. The mucosal cells expressed mitochondrial and cytosolic isoforms of creatine kinase and adenylate kinase (AK). Creatine (20 mM) and AMP (2 mM) markedly stimulated mitochondrial respiration in the presence of submaximal ADP or ATP concentrations, and creatine reduced apparent Km for ADP in stimulation of respiration, which indicates the functional coupling of mitochondrial kinases to oxidative phosphorylation. Addition of exogenous cytochrome c increased ADP-dependent respiration, and the large-scale cytochrome c effect (>or=20%) was associated with suppressed stimulation of respiration by creatine and AMP in the mucosal preparations. These results point to the impaired mitochondrial outer membrane, probably attributed to the pathogenic effects of Helicobacter pylori. Compared with the corpus mucosa, the antral mucosa exhibited greater sensitivity to such type of injury as the prevalence of the large-scale cytochrome c effect was twice higher among the latter specimens. Active chronic gastritis was associated with decreased respiratory capacity of the corpus mucosa but with its increase in the antral mucosa. In conclusion, human gastric mucosal cells express the mitochondrial and cytosolic isoforms of CK and AK participating in intracellular energy transfer systems. Gastric mucosa disease is associated with the altered functions of these systems and oxidative phosphorylation.
authors.affiliation: Department of Pathophysiology, Faculty of Medicine, Univ. of Tartu, 19 Ravila St., 50411 Tartu, Estonia.
authors.forename: Marju
authors.initials: M
authors.lastname: Gruno
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Peet
authors.forename: Evelin
authors.initials: E
authors.lastname: Seppet
authors.forename: Lumme
authors.initials: L
authors.lastname: Kadaja
authors.forename: Kalju
authors.initials: K
authors.lastname: Paju
authors.forename: Margus
authors.initials: M
authors.lastname: Eimre
authors.forename: Ehte
authors.initials: E
authors.lastname: Orlova
authors.forename: Margot
authors.initials: M
authors.lastname: Peetsalu
authors.forename: Andres
authors.initials: A
authors.lastname: Tein
authors.forename: Jaan
authors.initials: J
authors.lastname: Soplepmann
authors.forename: Uwe
authors.initials: U
authors.lastname: Schlattner
authors.forename: Ants
authors.initials: A
authors.lastname: Peetsalu
authors.forename: Enn K
authors.initials: EK
authors.lastname: Seppet
mesh_terms: D000263:Adenylate Kinase / Q000235:genetics / Q000378:metabolism*; D000368:Aged; D052281:Creatine Kinase, Mitochondrial Form / Q000235:genetics / Q000378:metabolism*; D045304:Cytochromes c / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005753:Gastric Mucosa / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000201:enzymology*; D009130:Muscle, Smooth / Q000201:enzymology; D010085:Oxidative Phosphorylation; D011706:Pyloric Antrum / Q000201:enzymology
chemical_list: D045304:Cytochromes c; D052281:Creatine Kinase, Mitochondrial Form; D000263:Adenylate Kinase