St-Pierre 2000 Am J Physiol Regul Integr Comp Physiol

St-Pierre J, Tattersall GJ, Boutilier RG (2000) Metabolic depression and enhanced O2 affinity of mitochondria in hypoxic hypometabolism. Am J Physiol Regul Integr Comp Physiol 279:R1205-14.

» PMID: 11003985 Open Access

St-Pierre J, Tattersall GJ, Boutilier RG (2000) Am J Physiol Regul Integr Comp Physiol

Abstract: This study examined whether the steady-state hypometabolism seen in overwintering frogs (Rana temporaria) is reflected at the mitochondrial level either by a reduction in their resting (state 4) and active (state 3) respiration rates and/or by increases in O₂ affinity. We isolated mitochondria from the skeletal muscle of cold-submerged frogs at different stages during their hibernation in normoxic and hypoxic water. A modest metabolic depression at the whole animal level (normoxic submergence) was not associated with a reduction in mitochondrial state 4 and state 3 respiration rates. However, mitochondria isolated from frogs that were submerged for 1 mo manifested an increase in their O₂ affinity compared with controls and with animals submerged for 4 mo. Hypometabolism was more pronounced at the whole animal level during hypoxic submergence and was accompanied by 1) a reduction in mitochondrial state 4 and state 3 rates and 2) an increase in the O₂ affinity of mitochondria. These findings demonstrate that metabolic depression can be reflected at all levels of biological organization in hypoxia-tolerant animals. • Keywords: Frog, Hypoxia, State 3, State 4, P50

Labels: MiParea: Respiration, Comparative MiP;environmental MiP 

Stress:Ischemia-reperfusion, Temperature  Organism: Amphibians  Tissue;cell: Skeletal muscle  Preparation: Isolated mitochondria 

Regulation: Oxygen kinetics  Coupling state: LEAK, OXPHOS  Pathway: N  HRR: Oxygraph-2k