Oxygen dependent energetics of anoxia-tolerant and anoxia-intolerant hepatocytes

KRUMSCHNABEL G, SCHWARZBAUM PJ, LISCH J, BIASI C, WIESER W.

JOURNAL OF EXPERIMENTAL BIOLOGY

COMPANY OF BIOLOGISTS LTD

Año: 2000 p. 951 - 959

0022-0949

The oxygen-dependence of cellular energetics wasinvestigated in hepatocytes from goldfish Carassius auratus(anoxia-tolerant) and rainbow trout Oncorhynchus mykiss(anoxia-intolerant). In goldfish hepatocytes, anapproximately 50 % reduction in the rate of oxygenconsumption was observed in response to both acute andprolonged hypoxia, the latter treatment shifting thethreshold for this reduction to a higher oxygen level. Aconcomitant increase in the rate of lactate production didnot compensate for the decreased aerobic ATP supply,resulting in an overall metabolic depression of 26 % duringacute hypoxia and of 42 % during prolonged hypoxia.Trout hepatocytes showed a similar suppression of cellularrespiration after prolonged hypoxia but were unresponsiveto acute hypoxia. Similarly, the rate of lactate productionwas unaltered during acute hypoxia but was increasedduring prolonged hypoxia, metabolic depressionamounting to 7% during acute hypoxia and 30 % duringprolonged hypoxia. In both species, the affinity ofhepatocytes for oxygen decreased during hypoxia, but thisalteration was not sufficient in absolute terms to accountfor the observed decrease in aerobic ATP supply. Proteinsynthesis was suppressed in both cell types under hypoxia,whereas Na+/K+-ATPase activity decreased in trout but notin goldfish hepatocytes, emphasising the importance ofmembrane function in these cells during conditions oflimited energy supply.