Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats
Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats
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DOI：
10.1152/jappl.1998.84.5.1716
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发表时间：
1998-05-01
影响因子：
3.3
通讯作者：
McCue, SA
中科院分区：
文献类型：
--
作者：
Adams, GR;McCue, SA
胰岛素样生长因子I（IGF-I）肽水平已被证明在过载的骨骼肌中增加（G。R.亚当斯和F.哈达德81：2509-2516，1996）。在该研究中，IGF-I的增加被发现先于肌肉蛋白质的可测量的增加，并且与肌肉DNA含量的增加相关。本研究旨在验证直接输注IGF-I会导致肌肉DNA增加以及肌肉大小的各种测量的假设。将0.9%生理盐水或非全身剂量的IGF-I直接输注到大鼠的非承重肌肉胫骨前肌（TA）中，通过连接到皮下微渗透泵的有孔导管。盐水输注对TA肌肉的质量、蛋白质含量或DNA含量没有影响。局部IGF-I输注对体重或心脏重量无影响。注入侧TA肌的绝对重量比对侧TA肌的绝对重量增加约9%（P < 0.05）。注射IGF-I后，TA肌总蛋白和DNA含量显著增加（P < 0.05）。作为这些协调变化的结果，过度营养的TA的DNA-蛋白质比率与对侧肌肉的DNA-蛋白质比率相似。这些结果表明，IGF-I可能直接刺激蛋白质合成和卫星细胞增殖等过程，导致骨骼肌肥大。
Insulin-like growth factor I(IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result iu an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was similar to 9% greater (P < 0.05) than that of the contralateral TA muscles. IGF-I infusion resulted in significant increases in the total protein and DNA content of TA muscles (P < 0.05). As a result of these coordinated changes, the DNA-to-protein ratio of the hyper trophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result; in skeletal muscle hypertrophy.