Zinc deficiency-induced anorexia influences the distribution of serum insulin-like growth factor-binding proteins in the rat.
Zinc (Zn) deficiency can result in severe growth retardation in mammals, and in a number of animal model systems it leads to low circulating insulin-like growth factor-I (IGF-I) concentrations. Using a weanling male rat model and a number of feeding schemes, we show that in addition to lower circulating IGF-I concentrations, Zn deficiency leads to alterations in the distribution of serum IGF-binding proteins (IGFBPs). Serum from Zn-deficient animals labeled in vitro with [125I]IGF-I displayed three peaks of tracer activity: 150 kd (IGFBP-3), 37 kd (IGFBP-2 and -1), and 8 kd (free [125I]IGF-I). Relative to controls, Zn-deficient animals demonstrated more tracer binding in the 37-kd region, whereas less was found in the 150- and 8-kd peaks. Serum from chronically calorie-restricted fed animals displayed [125I]IGF-I binding profiles similar to Zn-deficient serum, implicating Zn deficiency-induced anorexia as the principle factor underlying both the lower circulating IGF-I and the alterations in IGFBP profiles. Concentrations of IGFBP-4 were unaffected by diet manipulation based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)/Western ligand blot (WLB) analysis.
D000818:Animals; D000855:Anorexia / Q000097:blood* / Q000209:etiology*; D015153:Blotting, Western; D001835:Body Weight; D002850:Chromatography, Gel; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D002149:Energy Intake; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000097:blood; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007457:Iodine Radioisotopes; D008297:Male; D011863:Radioimmunoassay; D011897:Random Allocation; D051381:Rats; D015032:Zinc / Q000097:blood / Q000172:deficiency*
D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018974:Insulin-Like Growth Factor Binding Protein 4; D018969:Insulin-Like Growth Factor Binding Proteins; D007457:Iodine Radioisotopes; D007334:Insulin-Like Growth Factor I; D015032:Zinc