Identification of insulin-like growth factor (IGF)-I and IGF-binding protein in chylous ascites.
Insulin-like growth factors (IGFs) are bound by several IGF-binding proteins (IGFBPs) that appear to regulate IGF transportation, receptor binding and action. In adult human serum, most of IGFs are bound in a 150 kDa complex which could not cross the capillary wall. We measured IGF-I and IGFBPs in chyle by radioimmunoassay and western ligand blot. The concentration of IGF-I in chyle was only 15% of the corresponding serum level and most of IGF-I was found in 50 kDa complex. The IGFBPs profile in chyle, especially IGFBP-3, was different from that of serum. The concentration of IGFBP-3 in chyle was much less than in serum and the size of glycosylated IGFBP-3 was different from that of serum. However, the size and relative amount of IGFBP-1 and -2 in chyle were similar to serum. This finding indicates that IGF-I and IGFBPs in chyle to a large extent originate in the vascular system and only the 50 kDa complex can cross the capillary barrier.
Lee
D Y
DY
Department of Pediatrics, Institute for Medical Science, Chonbuk National University Medical School, Chonju, Korea.
D000328:Adult; D002915:Chylous Ascites / Q000378:metabolism*; D006801:Humans; D007223:Infant; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*
D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I