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...

In addition to their roles in IGF transport, the six IGF-binding proteins (IGFBPs) regulate cell activity in various ways. By sequestering IGFs away from the type I IGF receptor, they may inhibit mitogenesis, differentiation, survival, and other IGF-stimulated events. IGFBP proteolysis can reverse this inhibition or generate IGFBP fragments with novel bioactivity. Alternatively, IGFBP interacti...

IGF-1 is a growth-promoting polypeptide that is essential for normal growth and development. In serum, the majority of the IGFs exist in a 150-kDa complex including the IGF molecule, IGF binding protein 3 (IGFBP-3), and the acid labile subunit (ALS). This complex prolongs the half-life of serum IGFs and facilitates their endocrine actions. Liver IGF-1-deficient (LID) mice and ALS knockout (ALSK...

We have purified a protein from serum-free conditioned medium of the HT29 human colon adenocarcinoma cell line based on its ability to inhibit the proliferation of the same cell line. The purification procedure consisted of acid gel permeation, semipreparative, and analytical reversed-phase chromatographies. The high-pressure liquid chromatography-purified colon cancer cell growth inhibitor mig...

Insulin receptor substrates (IRSs) are well known to play crucial roles in mediating intracellular signals of insulin-like growth factors (IGFs)/insulin. Previously, we showed that IRS-1 forms high molecular mass complexes containing RNAs. To identify RNAs in IRS-1 complexes, we performed ultraviolet (UV) cross-linking and immunoprecipitation analysis using HEK293 cells expressing FLAG-IRS-1 an...

Problem statement: The IGFs play an important role in regulating somatic growth according to nutritional conditions. Polymorphisms of IGF gene are reported to be significantly associated with many traits. Approach: In these study 142 samples of DNA from Zel sheep were used for detecting the polymorphisms of promoter region of the Insulin-like Growth Factor-1 (IGF-1) gene. Therefore DNA extracte...

Robertson, J. Gray, David A. Belford, and F. John Ballard. Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions. Am. J. Physiol. 276 (Endocrinol. Metab. 39): E663–E671, 1999.—We have examined the role binding proteins have in regulating the clearance of exogenous growth factors from wounds. Hunt-Schilling chambers were subcutaneously implanted in rats, and the c...

The insulin-like growth factor binding protein (Igfbp) family consists of six members designated Igfbp1-6. Igfbps are involved in many vital biological functions. They physically interact with IGFs (IGF1 and IGF2) and act as carriers, thereby protecting IGFs from proteolytic degradation. Thus, they function as modulators of IGF activity. Furthermore, Igfbps have been reported to have IGF-indepe...

Limited proteolysis lowers affinity of insulin-like growth factor (IGF)-binding protein (IGFBP)-3 for bound IGFs, resulting in greater IGF bioavailability. Plasmin is one of many proteases that cleave IGFBP-3, and the plasmin system may regulate IGFBP-3 proteolysis and IGF bioavailability in cultured cells in vitro. A role for the plasmin system in IGFBP-3 proteolysis in vivo is suggested by da...

Insulin-like growth factors (IGFs), along with IGF-binding protein and IGF receptor, are well-known regulators in the growth and survival of vertebrates. In this study, we investigated the involvement of IGFs and protein variation during embryonic development of the olive flounder (Paralichthys olivaceus). Morphological stages were divided into six main developments as blastula, gastrula, cepha...