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Expression and localisation of IGF‐binding protein mRNAs in regenerating rat skeletal muscle
Author(s) -
Jennische EVA,
Hall CHRISTINA M.
Publication year - 2000
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1034/j.1600-0463.2000.d01-24.x
Subject(s) - connective tissue , regeneration (biology) , insulin like growth factor binding protein , biology , skeletal muscle , blot , growth factor , medicine , endocrinology , in situ hybridization , myocyte , microbiology and biotechnology , insulin like growth factor , messenger rna , receptor , biochemistry , gene , genetics
The expression of the insulin‐like growth factor‐binding proteins (IGFBP) ‐3, ‐4, ‐5 and ‐6 was investigated in neonatal, in normal adult and in regenerating rat skeletal muscle. Semi‐quantification was done by densitometric scannings of Northern blots. The expression of all investigated IGFBPs, with the exception of IGFBP‐5, was higher in neonatal than in adult muscle. During postischaemic regeneration the expression of all IGFBPs increased, but with different time schedules. IGFBP‐3 increased transiently during the early phase of regeneration, while IGFBP‐4, ‐5 and ‐6 increased during the later phase of regeneration. In situ hybridisation on regenerating muscle showed that the expression of the various IGFBPs was cell specific; thus, IGFBP 3 was mainly expressed in macrophages, IGFBP‐4 in connective tissue, IGFBP‐5 in regenerating muscle cells, and IGFBP‐6 in muscle cells, connective tissue and endothelium. Ligand blotting, using 125I‐IGF‐I as the ligand, showed a number of bands ranging between 24 and 44 kDa. Samples from neonatal and regenerating muscle contained much higher levels of all IGFBPs than those from normal adult muscle. An ordered and cell‐specific expression of IGFBPs, allowing a strict regulation of IGF actions, is probably necessary to ensure an optimal regeneration process.