Relationships between muscle mitochondrial metabolism and stress-induced corticosterone variations in rats
Pflügers Arch - Eur J Physiol. 2001-07-27; 443(2): 218-226
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1. Pflugers Arch. 2001 Nov;443(2):218-26.
Relationships between muscle mitochondrial metabolism and stress-induced
corticosterone variations in rats.
Duclos M(1), Martin C, Malgat M, Mazat JP, Chaouloff F, Mormède P, Letellier T.
(1)Laboratoire Neurogénétique et Stress, INSERM U471, Institut François Magendie,
Université Bordeaux II, 33077 Bordeaux Cedex, France.
In order to determine the effect of chronic and acute stress on muscle
mitochondrial metabolism, two strains of rats were selected on the basis of their
different hypothalamo-pituitary-adrenal (HPA) axis responses to different
stressors [Spontaneous Hypertensive Rats (SHR) and Lewis rats]. For 8 weeks
animals were stressed by daily exposure to either a novel environment (SHR: n=16,
Lewis: n=16) or forced exercise (SHR: n=16, Lewis: n=16). An unstressed group was
left undisturbed (SHR: n=5, Lewis: n=5). Half of the stressed animals (n=32) were
submitted to an acute stress (1-h immobilization). The mitochondrial responses of
plantaris muscle [cytochrome-c-oxidase (COX), citrate synthase and succinate
dehydrogenase activities, the latter two being measured as indices of functional
mitochondrial amount] in the presence of different physiological plasma
corticosterone (CORT) concentrations were analyzed. The novel environment and
forced exercise stress induced different levels of plasma CORT which were
negatively correlated with the amount of functional mitochondria in the plantaris
muscle. Therefore, a chronic intermittent stress is able to induce an increase in
plasma CORT which may be related to deleterious changes in muscle mitochondrial
metabolism. Lastly, the acute stress was not associated with a decrease in
functional mitochondria but with an increase in COX activity. This suggests that
the relationship between CORT and muscle mitochondrial metabolism depends both on
the level and duration of endogenous glucocorticoids exposure.
PMID: 11713647 [Indexed for MEDLINE]