Expression of insulin-like growth factor I (IGF-I) mRNA by some tumor cell lines of neuroectodermal origin has been described. To further explore the significance of IGF-I mRNA expression in these tumors, a more extensive analysis was performed. Most (9 of 10) neuroectodermal tumor cell lines with a t(11;22) translocation (primitive neuroectodermal tumor IPNETI, Ewing's sarcoma, esthesioneurobl...

Upon entry into the central nervous system (CNS), serum insulin-like growth factor-1 (IGF-I) modulates neuronal growth, survival, and excitability. Yet mechanisms that trigger IGF-I entry across the blood-brain barrier remain unclear. We show that neuronal activity elicited by electrical, sensory, or behavioral stimulation increases IGF-I input in activated regions. Entrance of serum IGF-I is t...

A family of six specific insulin-like growth factor binding proteins (IGFBPs) modulates the biological actions of the insulin-like growth factors, IGF-I and IGF-II. In the present study, we determined the binding affinity of purified human IGFBPs 1-6 for recombinant human IGF-II mutants whose binding to IGF-I, IGF-II/mannose 6-phosphate, and insulin receptors was previously reported (Sakano, K....

To determine if insulin-like growth factor binding protein-3 (IGFBP-3) can directly modulate the hormone-dependent steroidogenesis of thecal cells in vitro, thecal cells from large (≥ 8 mm) follicles were collected from cattle and cultured for 4 d. IGFBP-3 inhibited IGF-I-induced thecal cell progesterone and androstenedione production by 52% and 89%, respectively. In contrast, IGFBP-3 had no ef...

Insulin-like growth factor I (IGF-I) binding protein-5 (IGFBP-5) is produced by mesangial cells (MCs) and likely functions to modulate glomerular IGF-I activity. Although IGFBP-5 may be inhibitory for IGF-stimulated MC activity, preliminary studies suggested that IGFBP-5 acts directly on MCs. To investigate this further, we evaluated the effects of IGFBP-5 on rat MC migration. We found that the...

Background: The objective of this study was to evaluate serum IGF-I levels in postmenopausal women with breast cancer treated primarily with raloxifene. Methods: Twenty-two postmenopausal patients with operable, stage I or II, estrogen receptorpositive carcinomas participated in this study. Following confirmation of diagnosis, the patients received 60 mg of raloxifene for 28 days prior to defin...

IGF I is an ubiquitous peptide that activates a membrane tyrosine kinase receptor and has autocrine/paracrine effects on vascular smooth muscle cells. Thrombin activates a G-protein coupled receptor and is also a mitogen for vascular smooth muscle cells. To assess the potential role of IGF I as a mediator of thrombin's effects, we characterized expression of IGF I and of its receptor on vascula...

The Crk proto-oncogene product is an SH2 and SH3 domain-containing adaptor protein. We have previously demonstrated that Crk-II becomes rapidly tyrosine-phosphorylated in response to stimulation with insulin-like growth factor I (IGF-I) and might be involved in the IGF-I receptor signalling pathway. To determine whether this involvement includes the direct interaction of Crk-II with the cytopla...