Role of IGF-I and IGFBPs in the changes of mass and phenotype induced in rat soleus muscle by clenbuterol
Role of IGF-I and IGFBPs in the changes of mass and phenotype induced in rat soleus muscle by clenbuterol
复制标题
DOI：
10.1152/ajpendo.2002.282.1.e31
复制
发表时间：
2002-01-01
影响因子：
5.1
通讯作者：
Lebacq, J
中科院分区：
文献类型：
--
作者：
Awede, BL;Thissen, JP;Lebacq, J
Clenbuterol induces hypertrophy and a slow-to-fast phenotype change in skeletal muscle, but the signaling mechanisms remain unclear. We hypothesized that clenbuterol could act via local expression of insulin-like growth factor I (IGF-I). Administration of clenbuterol to 3-mo-old female Wistar rats resulted in a 10 and 13% increase of soleus muscle mass after 3 and 9 days, respectively, reaching 16% after 4 wk. When associated with triiodothyronine, clenbuterol induced a dramatic slow-to-fast phenotype change. In parallel, clenbuterol administration induced in soleus muscle a fivefold increase in IGF-I mRNA levels associated with an eightfold increase in IGF-binding protein (IGFBP)-4 and a fivefold increase of IGFBP-5 mRNA levels on day 3. This increased IGF-I gene expression was associated with an increase in muscle IGF-I content, already detected on day 1 and persisting until day 5 without increase in serum IGF-I concentrations. These data show that muscle hypertrophy induced by clenbuterol is associated with a local increase in muscle IGF-I content. They suggest that clenbuterol-induced muscle hypertrophy could be mediated by local production of IGF-I.
