Changes of cytosol glucocorticoid receptor and renal Na (+) -K (+) -ATPase activity after swimming training in rat
Peijie, B.; Zicai, D.; Tian, W.
Journal of Sports Medicine and Physical Fitness 47(2): 246-249
2007
ISSN/ISBN: 0022-4707 PMID: 17557067 Document Number: 614647
The aim of this study was to determine whether the down-regulation of glucocorticoid receptor (GR) by physical changes in plasma glucocorticoid hormones (GCs) is accompanied by changes in the responsiveness of target cells to GCs in rats. Normal male Sprague-Dawley rats were left to swim for 60 min. At 15 min and at 3, 12, 24 h after swimming training, groups of rats were sacrificed. The results show that exposure of rats to a 60-min swimming stress provokes corticosterone secretion, which results in a rapid depletion of GR from renal cytosol and the subsequent induction of the renal Na(+)-K(+)-ATPase. By employing RU38486 and Trilostane before swimming training, both the effects of GCs on regulating GR binding activity and related changes in GR binding capacity to Na(+)-K(+)-ATPase activity are also investigated. RU38486 was shown to reduce GR by about 80% and the inducing effort of GCs on Na(+)-K(+)-ATPase was prevented by pretreatment of RU38486 and Trilostane. These data suggest that physiological fluctuations in endogenous hormone secretion are sufficient to result not only in substantial cytosol GR down-regulation, but in a coordinate physiological response.