Effects of thyroxine supplement on serum insulin-like growth factor-binding activity in propylthiouracil induced hypothyroid cockerels.
In propylthiouracil (PTU)-fed (g/kg feed) hypothyroid cockerels, serum levels of growth hormone (GH), but not insulin-like growth factor (IGF)-1, tended to rise and those of IGF-binding activity to fall. Thyroxine (T4) supplement (200 micrograms/kg/day) to PTU-fed cockerels for 8 days produced a hyperthyroid state and reversed these serum parameters. A chromatographic analysis of serum proteins revealed that T4 supplement markedly enhanced the IGF-binding activity of a 30 kDa protein and slightly lowered that of a 150 kDa protein, suggesting that T4 increases unsaturated IGF-binding proteins by reducing circulating IGF-1 concentrations.
Morishita
D
D
Faculty of Bioresources, Mie University, Tsu, Japan.
Wakita
M
M
Hoshino
S
S
D000818:Animals; D000831:Animals, Newborn; D001798:Blood Proteins / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002352:Carrier Proteins / Q000097:blood; D002645:Chickens; D006980:Hyperthyroidism / Q000378:metabolism; D007037:Hypothyroidism / Q000097:blood* / Q000139:chemically induced; D018969:Insulin-Like Growth Factor Binding Proteins; D007457:Iodine Radioisotopes; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011441:Propylthiouracil; D011485:Protein Binding; D013002:Somatomedins / Q000378:metabolism*; D013961:Thyroid Gland / Q000187:drug effects; D013974:Thyroxine / Q000097:blood / Q000494:pharmacology*; D014284:Triiodothyronine / Q000097:blood
D001798:Blood Proteins; D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D007457:Iodine Radioisotopes; D013002:Somatomedins; D014284:Triiodothyronine; D011441:Propylthiouracil; D013974:Thyroxine