The effects of glucocorticoids (dexamethasone) on insulin-like growth factor-I, IGF-binding proteins, and growth in chickens.
The effect of glucocorticoids (dexamethasone) on circulating concentrations of insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBPs) was examined in young (2-week-old) chickens. Increasing dosages (6, 60, and 600 microg/kg) of dexamethasone resulted in progressive growth retardation as evidenced by decreased body-weight gain, reduced bone growth, and breast muscle weights, together with immunosuppression as indicated by decreased thymus and bursa weights. Plasma concentrations of IGF-I were progressively reduced with increased doses of dexamethasone. There were no changes in circulating IGFBPs except on Day 7 when binding activity of the 36-kDa IGFBP was increased by dexamethasone (6 microg/kg). It is speculated that similarities exist between the 36-kDa IGFBP and the mammalian IGFBP-1 based on the response to dexamethasone treatment.
Department of Animal Sciences, Rutgers--The State University of New Jersey, New Brunswick 08903, USA. Steven_._Leili@ccmail.bms.com
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D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D001852:Bone Lengthening / Q000662:veterinary; D002645:Chickens / Q000254:growth & development*; D003907:Dexamethasone / Q000008:administration & dosage*; D004334:Drug Administration Schedule / Q000662:veterinary; D004591:Electrophoresis, Polyacrylamide Gel; D005528:Foot; D007279:Injections, Subcutaneous / Q000662:veterinary; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood / Q000187:drug effects*; D007334:Insulin-Like Growth Factor I / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects / Q000502:physiology
D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone