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Insulinlike growth factor gene expression in rat muscle during reinnervation
Author(s) -
Glazner Gordon W.,
Ishii Douglas N.
Publication year - 1995
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880181214
Subject(s) - reinnervation , gene expression , endocrinology , gene , medicine , biology , growth factor , nerve growth factor , anatomy , neuroscience , genetics , receptor
Because insulinlike growth factors (IGFs) support motor axon regeneration, we tested whether the IGF genes expressed during the development of neuromuscular synapses are reexpressed in adult rat muscles during synapse regeneration. Following sciatic nerve crush, IGF‐II mRNAs per poly(A) + RNA, as well as per poly(A) + RNA per milligram muscle, were significantaly up‐regulated in denervated relative to intact contralateral gastrocnemius muscles. IGF‐II mRNAs were downregulated after the reestablishment of functional neuromuscular synapses, but remained up‐regulated when nerves were transected to prevent the reestablishment of synapses. These data are consistent with a model in which the IGF‐II gene is reexpressed during regeneration due to loss of nerve‐dependent feedback inhibition. There was a slight but significant increase in IGF‐I mRNAs per poly(A) + RNA per milligram muscle, probably as a consequence of muscle atrophy. These results show that IGF‐II gene expression is up‐regulated in muscle during the reestablishment of synapses. © 1995 John Wiley & Sons, Inc.