Aerobic training prevents dexamethasone-induced peripheral insulin resistance.
This study investigated how proteins of the insulin signaling cascade could modulate insulin resistance after dexamethasone (Dexa) treatment and aerobic training. Rats were distributed into 4 groups: sedentary control (SC), sedentary+Dexa (SD), trained control (TC), and trained+Dexa (TD), and underwent aerobic training for 70 days or remained sedentary. Dexa was administered during the last 10 days (1 mg · kg(-1) per day i. p.). After 70 days, an intraperitoneal glucose tolerance test (ipGTT) was performed. Protein levels of IRS-1, AKT, and PKC-α in the tibialis anterior (TA) muscle were identified using Western blots. Dexa treatment increased blood glucose and the area under the curve (AUC) of ipGTT. Training attenuated the hyperglycemia and the AUC induced by Dexa. Dexa reduced IRS-1 (- 16%) and AKT (- 43%) protein level with no changes in PKC-α levels. Moreover, these effects on IRS-1 and AKT protein level were prevented in trained animals. These results show for the first time that aerobic exercise prevented reductions of IRS-1 and AKT level induced by Dexa in the TA muscle, suggesting that aerobic exercise is a good strategy to prevent Dexa-induced peripheral insulin resistance.
Department of Physiological Science, Federal University of São Carlos - UFSCAR, São Carlos, Brazil.
T J
TJ
Dionísio
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
J C A
JC
Louzada
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
B A
BA
Viscelli
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
E J
EJ
Dionísio
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
A M
AM
Martuscelli
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
M
M
Barel
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
O A B
OA
Perez
Department of Physical Education, UNESP - São Paulo State University, Bauru, Brazil.
J R
JR
Bosqueiro
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, USP, Bauru, Brazil.
D T
DT
Brozoski
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, USP, Bauru, Brazil.
C F
CF
Santos
Department of Physiological Science, Federal University of São Carlos - UFSCAR, São Carlos, Brazil.
S L
SL
Amaral
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D005951:Glucose Tolerance Test; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D055504:Insulin Receptor Substrate Proteins; D003907:Dexamethasone