Original articles  BIOCHEMISTRY 

The Journal of Sports Medicine and Physical Fitness 2004 September;44(3):322-7

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Long-term endurance training induced changes in glucocorticoid receptors concentrations in rat and in man

Peijie C. ¹, Renbao X. ², Xinming T. ¹

¹ Department of Sports Medicine Shanghai Institute of Physical Educations, Shanghai, China 2 Department of Patho-physiology Second Military College, Shanghai, China

Aim. The respon­sive­ness of ­target ­cells to glu­co­cor­ti­coids is ­directly ­related to the ­number and the func­tional ­state of intra­cel­lular glu­co­cor­ti­coid recep­tors (GR), ­which medi­ated the ­role of glu­co­cor­ti­coids. ­Although the ­effects of ­acute ­training on GR ­have ­been ­well char­ac­ter­ized, ­less is ­known ­about the ­effects of ­chronic ­training on GR. The pur­pose of the ­present ­study was to ­describe the ­effects of ­long-­term endu­rance ­training on GR.
­Methods. ­Male ­Sprague-­Dawley ­rats ­were ­divided ­into 2 ­groups at ­random, 7 as con­trols and exer­cisers (swim­ming 40-50 min/day for 80 ­days), respec­tively. All ­rats ­were sac­ri­ficed 24 ­hours ­after ­their ­last ­training ses­sion for meas­ure­ments of the GR in ­liver and ­brain ­cytosol and ­thymus ­cells by radio­ligand ­binding ­assay ­with 3H-dex­a­meth­a­sone. ­This ­study was ­also car­ried out on 8 ­trained ­adult, 8 ­aged as ­well as 6 ­retired ath­letes, ­whose GR in periph­eral leu­ko­cytes ­were ana­lyzed.
­Results. GR in ­hepatic ­cytosol and ­intact ­thymus ­cells of ­rats ­were sig­nif­i­cantly ­lower in exer­cise ­group ­than ­those in the con­trols. But the ­apparent dis­so­ci­a­tion con­stant (kd) was not ­changed. The GR in ­brain ­cytosol of ­rats indi­cated no sig­nif­i­cant reduc­tion ­after ­training. The GR in periph­eral leu­ko­cytes of the ­adult and ­aged ath­letes ­were ­also sig­nif­i­cantly ­lower ­than ­that in the con­trols. How­ever, ­there was no sig­nif­i­cant dif­fer­ence ­between the GR in the ­retired ath­letes and ­that in the con­trols.
Con­clu­sion. ­This ­study dem­on­strated ­that ­long-­term endu­rance ­training ­could ­lead to a ­decrease in GR and ­that the ­changes in GR ­were rever­sible ­during ­training. The pos­sible mech­a­nisms and the phys­io­log­ical sig­nif­i­cance of ­these ­changes ­need to be deter­mined.