Physiological inhibition of growth hormone secretion by both insulin-like growth factors-I and -II in chickens.
1. The role of both insulin-like growth factors (IGF)-I and -II in regulation of growth hormone (GH) secretion in chickens was examined. Seven-week-old male broiler chickens were injected intravenously (i.v.) with recombinant human IGF-I or IGF-II or specific anti-IGF-I or IGF-II immunoglobulins. Blood samples were taken before treatment and at 15 min intervals afterwards for 1 h. Controls received saline i.v. 2. Both IGF-I and IGF-II administration resulted in a rapid, significant decrease in plasma GH concentrations, but the concentrations of both triiodothyronine and thyroxine remained unchanged. 3. Immunisation against both IGF-I and IGF-II produced a significant elevation in plasma GH. 4. These data show that both IGFs can regulate GH concentrations in birds. Furthermore, the immunoneutralisation data suggest that these hormones have a physiological role in the regulation of GH secretion.
Spencer
G S
GS
Laboratory for Physiology and Immunology of Domestic Animals, Catholic University of Leuven, Heverlee, Belgium.
Buyse
J
J
Decuypere
E
E
Rahimi
G
G
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002645:Chickens; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000276:immunology / Q000493:pharmacokinetics / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000276:immunology / Q000493:pharmacokinetics / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D011994:Recombinant Proteins / Q000097:blood / Q000276:immunology / Q000494:pharmacology; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D000906:Antibodies; D011994:Recombinant Proteins; D014284:Triiodothyronine; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone; D013974:Thyroxine