Differential adaptations of insulin-like growth factor-I, basic fibroblast growth factor, and leukemia inhibitory factor in the plantaris muscle of rats by mechanical overloading: an immunohistochemical study.
We investigated changes in several growth factors in the rat plantaris muscle produced by mechanical overloading by ablation of synergists using immunohistochemistry. At 1 and 3 days post surgery, the insulin-like growth factor-I (IGF-I) level was slightly increased in the cytosol and markedly increased in the invading cells of the extracellular space. Thereafter, the IGF-I immunoreactivity evoked by overloading rapidly decreased to the normal level. The level of leukemia inhibitory factor (LIF), which was not shown to change at 1 day post surgery, was increased in the cytosol at 3, 5, 7 and 10 days and at 2 weeks. Basic fibroblast growth factor (bFGF) immunoreactivity did not change during the entire period of overloading (1 day-3 weeks post surgery). These results indicate that the elevations of the levels of IGF-I and LIF show differential time course in the plantaris muscle subjected to functional overload. Furthermore, bFGF appears not to be related to the compensatory hypertrophy produced by overloading.
Sakuma
K
K
Department of Physiology, Aichi Human Service Center, Japan. k46336u@nucc.cc.nagoya-u.ac.jp
Watanabe
K
K
Totsuka
T
T
Uramoto
I
I
Sano
M
M
Sakamoto
K
K
D000222:Adaptation, Physiological; D000818:Animals; D003600:Cytosol / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000032:analysis / Q000378:metabolism*; D006131:Growth Inhibitors / Q000032:analysis / Q000378:metabolism*; D006984:Hypertrophy; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism*; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000032:analysis / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000166:cytology / Q000473:pathology / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D016474:Weight-Bearing / Q000502:physiology
D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines; D016222:Fibroblast Growth Factor 2; D007334:Insulin-Like Growth Factor I