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Titolo:
The use of extracellular lactate as an oxidative substrate in the oxygen-limited frog
Autore:
Donohoe, PH; Boutilier, RG;
Indirizzi:
Univ Cambridge, Dept Zool, Cambridge CB2 3EJ, England Univ Cambridge Cambridge England CB2 3EJ ool, Cambridge CB2 3EJ, England
Titolo Testata:
RESPIRATION PHYSIOLOGY
fascicolo: 2-3, volume: 116, anno: 1999,
pagine: 171 - 179
SICI:
0034-5687(19990803)116:2-3<171:TUOELA>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
METABOLIC-RATE DEPRESSION; RANA-CATESBEIANA; ACID-BASE; HYPOXIA; ANAEROBIOSIS; BLOOD; PH;
Keywords:
amphibian, frog; hibernation, anaerobic metabolism; hypoxia, hibernation; lactic acid, shuttle, hypoxic hibernation; metabolism, anaerobic, hibernating;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Donohoe, PH Univ Calif San Francisco, Dept Anesthesia, 513 Parnassus Ave, San Francisco, CA 94143 USA Univ Calif San Francisco 513 Parnassus Ave San Francisco CA USA 94143
Citazione:
P.H. Donohoe e R.G. Boutilier, "The use of extracellular lactate as an oxidative substrate in the oxygen-limited frog", RESP PHYSL, 116(2-3), 1999, pp. 171-179

Abstract

The aim of this paper was to determine the contribution of anaerobic respiration to metabolism in hibernating frogs exposed to progressive hypoxia. Previous studies on acute exposure to hypoxia had shown that even at ambientP-O2 levels of 60 mmHg, cold-submerged frogs were obliged to recruit anaerobic pathways to provide enough energy to maintain the ATP and phosphocreatine concentrations of tissues perfectly homeostatic. In the current experiments, we exposed frogs to hypoxic conditions gradually to reveal that 30 mmHg probably represents a "threshold P-O2 at which survival is still possible, at least for 1 week. However, by the time this threshold was reached, liver glycogen reserves were exhausted and the frog must rely thereafter on its quantitatively large store of skeletal muscle glycogen. The lactate produced as a by-product of glycolytic ATP production did not accumulate in themuscle but was preferentially exported to the plasma where it was held against a sizeable extracellular to intracellular gradient. The results suggest that the exported lactate was 'shuttled' between a poorly-perfused skeletal muscle and a more highly-perfused and oxygenated core of the animal where it could act as both a substrate for direct oxidation or for gluconeogenesis. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/07/20 alle ore 12:24:01