The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation.
The effects of several human and chicken insulin-like growth factor (IGF) analogs on turkey satellite cell and embryonic myoblast proliferation were examined in serum-free medium. Similar rates of proliferation were observed when human or chicken IGF-I or IGF-II (13.1 nM) was administered to satellite cells. The biopotency of two analogs, which were modified to prevent interaction with IGF-binding proteins, was also examined. Human Des(1-6)IGF-II was equipotent to native human and chicken IGF-II. However, the chicken LR3 IGF-I analog was significantly less active toward satellite cells and embryonic myoblasts compared with chicken IGF-I. Human [Leu27] IGF-II, an analog designed to have reduced affinity to the IGF Type I receptor but unaltered binding to IGF-binding proteins, had a diminished effect on cell proliferation. Examination of IGF receptor binding characteristics revealed that chicken LR3 IGF-I had reduced ability to compete with [125I]hIGF-I for binding to satellite cells or embryonic myoblasts compared with chicken IGF-I. The observed biological responses to IGF suggest that IGF-binding proteins have little effect on Type I IGF receptor action in these cell types in serum-free medium. The results also suggest that alterations of the IGF molecule to prevent interaction with binding proteins may also alter receptor binding affinity.
Pesall
J E
JE
Department of Animal and Range Sciences, South Dakota State University, Brookings 57007-0392, USA.
McFarland
D C
DC
McMurtry
J P
JP
Clapper
J A
JA
Francis
G L
GL
Gilkerson
K K
KK
D000818:Animals; D001667:Binding, Competitive; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects*; D002645:Chickens; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000031:analogs & derivatives* / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000031:analogs & derivatives* / Q000494:pharmacology; D007457:Iodine Radioisotopes; D018482:Muscle, Skeletal / Q000166:cytology* / Q000196:embryology*; D014422:Turkeys / Q000196:embryology*
D007457:Iodine Radioisotopes; C084339:LR(3)IGF-I; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II