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Titolo:
MICROCALORIMETRIC MEASUREMENT OF REVERSIBLE METABOLIC SUPPRESSION INDUCED BY ANOXIA IN ISOLATED HEPATOCYTES
Autore:
BUCK LT; HOCHACHKA PW; SCHON A; GNAIGER E;
Indirizzi:
UNIV BRITISH COLUMBIA,DEPT ZOOL,ROOM 1386 HSE,BOX 0542 VANCOUVER V6T 1Z4 BC CANADA LUND UNIV,CTR CHEM,DIV THERMOCHEM S-22100 LUND SWEDEN UNIV CLIN INNSBRUCK,DIV RES,DEPT TRANSPLANT SURG A-6020 INNSBRUCK AUSTRIA
Titolo Testata:
The American journal of physiology
fascicolo: 5, volume: 265, anno: 1993,
parte:, 2
pagine: 180001014 - 180001019
SICI:
0002-9513(1993)265:5<180001014:MMORMS>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
CHRYSEMYS-PICTA-BELLII; SEVERELY HYPOXIC WATER; LONG-TERM SUBMERGENCE; ACID-BASE; COMPARATIVE PHYSIOLOGY; ANAEROBIC METABOLISM; HEAT DISSIPATION; GAS-EXCHANGE; TURTLE; OXYGEN;
Keywords:
PASTEUR EFFECT; CHRYSEMYS-PICTA-BELLII; TURTLE; DIRECT AND INDIRECT CALORIMETRY; ENTHALPY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
L.T. Buck et al., "MICROCALORIMETRIC MEASUREMENT OF REVERSIBLE METABOLIC SUPPRESSION INDUCED BY ANOXIA IN ISOLATED HEPATOCYTES", The American journal of physiology, 265(5), 1993, pp. 180001014-180001019

Abstract

The metabolic suppression due to anoxia in hepatocytes from the anoxia-tolerant turtle Chrysemys picta bellii was measured directly using microcalorimetric techniques. The normoxic heat flux from hepatocytes in suspension (25-degrees-C) was 1.08 +/- 0.08 mW/g cells and decreasedby 76% to 0.26 +/- 0.03 mW/g cells in response to anoxic incubation. After an acute decrease in temperature (to 10-degrees-C) anoxic heat flux dropped by 96% relative to the normoxic control at 25-degrees-C. The relative decrease in heat flux at both temperatures was similar, 76% at 25-degrees-C and 68% at 10-degrees-C. From the caloric equivalentof glycogen fermentation to lactate the heat flux from lactate production was calculated to be -93 muW/g cells (25-degrees-C), and this accounted for 36% of the anoxic heat flux. When the enthalpy change associated with the release of free glucose (from glycogen breakdown) is considered, an additional 6% of the anoxic heat flux can be accounted for. Therefore, a portion of the anoxic heat flux is unaccounted for (58%), resulting in an ''exothermic gap. '' This differs from the normoxically incubated hepatocytes where the indirect calorimetric measurementof heat flux (hepatocyte O2 consumption) could fully account for the calorimetrically measured heat flux. When normoxic hepatocytes were inhibited with cyanide, a rapid suppression in heat flux was observed. Because rapid reequilibration to a lower, cyanide-induced steady state occurred in <15 min, it is also assumed that there is no short-term Pasteur effect in this tissue. There also does not appear to be a long-term sustained glycolytic activation; this conclusion is supported by the similarity of normoxic and anoxic rates of glucosyl unit entry intoglycolysis over a 10-h incubation period. Interestingly, the additionof 2,4-dinitrophenol to anoxic hepatocytes caused heat flux to increase by 30%, and this is suggestive of some aspect of mitochondrial metabolism being active.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 05:17:02