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Titolo:
Two research paths for probing the roles of oxygen in metabolic regulation
Autore:
Hochachka, PW;
Indirizzi:
Univ British Columbia, Dept Zool, Vancouver, BC V6T 1Z4, Canada Univ British Columbia Vancouver BC Canada V6T 1Z4 ver, BC V6T 1Z4, Canada Univ British Columbia, Sports Med Div, Vancouver, BC V6T 1Z4, Canada Univ British Columbia Vancouver BC Canada V6T 1Z4 ver, BC V6T 1Z4, Canada
Titolo Testata:
BRAZILIAN JOURNAL OF MEDICAL AND BIOLOGICAL RESEARCH
fascicolo: 6, volume: 32, anno: 1999,
pagine: 661 - 672
SICI:
0100-879X(199906)32:6<661:TRPFPT>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
ATP TURNOVER RATES; ENZYMATIC FLUX CAPACITIES; SKELETAL-MUSCLE; NARCINE-BRASILIENSIS; SIGNAL-TRANSDUCTION; MAGNETIC-RESONANCE; HUMMINGBIRD FLIGHT; CELL; HOMEOSTASIS; GLYCOLYSIS;
Keywords:
oxygen delivery; oxygen regulation; intracellular perfusion; intracellular diffusion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Hochachka, PW Univnadatish Columbia, Dept Zool, 6270 Univ Blvd, Vancouver,BC V6T 1Z4, Ca Univ British Columbia 6270 Univ Blvd Vancouver BC Canada V6T 1Z4
Citazione:
P.W. Hochachka, "Two research paths for probing the roles of oxygen in metabolic regulation", BRAZ J MED, 32(6), 1999, pp. 661-672

Abstract

Examination of a number of cell and whole-organism level systems identifies ATP concentration as a key parameter of the interior milieu that is nearly universally 'homeostatic'; it is common to observe no change in ATP concentration even while change in its turnover rate can increase or decrease bytwo orders of magnitude or more. A large number of other intermediates of cellular metabolism are also regulated within narrow concentration ranges, but none seemingly as precisely as is [ATP]. In fact, the only other metabolite in aerobic energy metabolism that is seemingly as 'homeostatic' is oxygen - at least in working muscles where myoglobin serves to buffer oxygen concentrations at stable and constant values at work rates up to the aerobicmaximum. In contrast to intracellular oxygen concentration, a 1:1 relationship between oxygen delivery and metabolic rate is observed over biologically realistic and large-magnitude changes in work. The central regulatory question is how the oxygen delivery signal is transmitted to the intracellular metabolic machinery. Traditional explanations assume diffusion as the dominant mechanism, while proponents of an ultrastructurally dominated view ofthe cell assume an intracellular perfusion system to account for the data which have been most perplexing to metabolic biochemistry so far: the striking lack of correlation between changes in pathway reaction rates and changes in concentrations of pathway substrates, including oxygen and pathway intermediates. Tissues such as skeletal and cardiac muscles must sustain verylarge-scale changes in ATP turnover rate during equally large changes in work. In many skeletal muscles these changes can exceed 100-fold.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/09/20 alle ore 08:03:36