Article

ANG II is required for optimal overload-induced skeletal muscle hypertrophy.

Department of Integrative Biology and Pharmacology, University of Texas--Houston Health Science Center, Houston, Texas 77030, USA.
AJP Endocrinology and Metabolism (impact factor: 4.75). 02/2001; 280(1):E150-9. pp.E150-9
Source: PubMed

ABSTRACT ANG II mediates the hypertrophic response of overloaded cardiac muscle, likely via the ANG II type 1 (AT(1)) receptor. To examine the potential role of ANG II in overload-induced skeletal muscle hypertrophy, plantaris and/or soleus muscle overload was produced in female Sprague-Dawley rats (225-250 g) by the bilateral surgical ablation of either the synergistic gastrocnemius muscle (experiment 1) or both the gastrocnemius and plantaris muscles (experiment 2). In experiment 1 (n = 10/group), inhibiting endogenous ANG II production by oral administration of an angiotensin-converting enzyme (ACE) inhibitor during a 28-day overloading protocol attenuated plantaris and soleus muscle hypertrophy by 57 and 96%, respectively (as measured by total muscle protein content). ACE inhibition had no effect on nonoverloaded (sham-operated) muscles. With the use of new animals (experiment 2; n = 8/group), locally perfusing overloaded soleus muscles with exogenous ANG II (via osmotic pump) rescued the lost hypertrophic response in ACE-inhibited animals by 71%. Furthermore, orally administering an AT(1) receptor antagonist instead of an ACE inhibitor produced a 48% attenuation of overload-induced hypertrophy that could not be rescued by ANG II perfusion. Thus ANG II may be necessary for optimal overload-induced skeletal muscle hypertrophy, acting at least in part via an AT(1) receptor-dependent pathway.

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Keywords

28-day overloading protocol attenuated plantaris
 
ANG II
 
ANG II perfusion
 
ANG II type 1
 
bilateral surgical ablation
 
exogenous ANG II
 
experiment 1
 
experiment 2
 
female Sprague-Dawley rats
 
lost hypertrophic response
 
nonoverloaded
 
optimal overload-induced skeletal muscle hypertrophy
 
oral administration
 
overload-induced skeletal muscle hypertrophy
 
overloaded cardiac muscle
 
perfusing overloaded soleus muscles
 
soleus muscle hypertrophy
 
soleus muscle overload
 
synergistic gastrocnemius muscle
 
total muscle protein content
 

S E Gordon