We have reported that pretreatment of rat FRTL-5 thyroid cells with thyrotropin (TSH) markedly potentiates the mitogenic response to insulin-like growth factor-I (IGF-I). The present study was undertaken to determine whether the augmentation by cAMP of IGF-I-dependent tyrosine phosphorylation of known IGF-I receptor substrates plays an important role in the cAMP-dependent potentiation of DNA sy...

Insulin-like growth factor I (IGF-I) binding sites were characterized in normal and neoplastic endometrium. The characteristics of the endometrial IGF-I receptor are similar to those reported for other tissues. The binding of I25I-IGF-I to the endometrial membranes is saturable and time, temperature, and pH dependent. The I25I-IGF-I binding activity to the membranes obtained from differentiated...

Insulin-like growth factors I and II (IGF-I and II) and insulin are chemotactic agents for the human melanoma cell line A2058. As shown in this report, the motility receptor mediating this response is the heterodimeric type I IGF receptor. These three factors are able to compete with 125I-labeled IGF-I for binding to the cell surface with IC50 values equal to approximately 2 (IGF-I), approximat...

To determine whether fish have an insulin-like growth factor II/mannose 6-phosphate (IGF-II/M6-P) receptor similar to that of mammals, we have performed binding, cross-linking, and immunoprecipitation experiments with wheat-germ-agglutinin- and mannose 6-phosphate (M6-P)-affinity-purified receptor preparations from fish embryos. In both receptor preparations, IGF-II binding was specific, becaus...

We examined the potential function of Src in human pancreatic carci noma. Overexpression of kinase-activated SrcY527F resulted in a signif icant increase of insulin-like growth factor I (IGF-I)-dependent cell pro liferation in the cell line PANC-1. Western blotting and competition binding studies demonstrated 2.3 ±0.2-fold increase in IGF-I receptor expression and 2.8 ±0.4-fold increase in IG...

We examined the potential function of Src in human pancreatic carcinoma. Overexpression of kinase-activated SrcY527F resulted in a significant increase of insulin-like growth factor I (IGF-I)-dependent cell proliferation in the cell line PANC-1. Western blotting and competition binding studies demonstrated 2.3 +/- 0.2-fold increase in IGF-I receptor expression and 2.8 +/- 0.4-fold increase in I...

The ED50 of insulin-like growth factor (IGF)-I-stimulated alpha-aminoisobutyric acid (AIB) uptake (mean +/- SD) in cultured fibroblasts from a child with short stature that we have reported (1.40 +/- 0.24 nM), is significantly higher than the ED50 of IGF-I-stimulated AIB uptake in fibroblasts from 11 normal subjects (0.42 +/- 0.12 nM) and from 127 short children (0.35 +/- 0.11 nM). Similarly, t...

A GnRH-expressing neuronal cell line (NLT) was used to determine whether insulin-like growth factor I (IGF-I) regulates GnRH gene expression. A receptor-binding assay demonstrated the expression of IGF-I receptors on NLT cells. Activation of IGF-I receptors induced the Ras/Raf-1/mitogen-activated protein kinase pathway and increased c-fos expression. NLT cells treated with IGF-I underwent cell ...

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...

We have previously shown that both HCG and insulin-like growth factor-II (IGF-II) stimulate trophoblastic invasion. Furthermore, the invasion-promoting function of IGF-II resulted from IGF-II mannose 6-phosphate receptor (IGF-II/M6PR) activation. Since HCG and IGF-II did not have an additive effect on cell migration of extravillous trophoblast (EVT) cell line, HTR-8 SVneo, we hypothesized that ...