To address the question of insulin-like growth factor (IGF) I localization and synthesis in kidney, we used two complementary experimental approaches: immunohistochemistry of fixed paraffin-embedded rat kidney sections; and measurement of IGF I mRNA in isolated components of the rat nephron, using a highly sensitive and specific solution hybridization assay. Immunostainable IGF I was localized ...

Insulin-like growth factors I and II (IGF I and II) are polypeptides with both growth-promoting and insulin-like metabolic effects. Immunoreactive IGF I is present in the retina and both IGF I and II are present in vitreal fluid. The type I and type II IGF receptors are also localized within the neural retina. The presence of IGFs and IGF receptors within the eye suggests a possible growth-prom...

Using affinity cross-linking techniques, we report the presence of type I IGF and type II IGF receptors in Madin-Darby canine kidney cells, a line of cells lacking insulin receptors. The IGF receptors were further characterized by competition binding studies and found to be similar to IGF receptors in other tissue types. In Madin-Darby canine kidney cells, the type I IGF receptor binds IGF-I gr...

Recombinant human insulin-like growth factors (rhIGF-I and rhIGF-II) and human insulin promoted the differentiation of spermatogonia into primary spermatocytes in newt testes fragments cultured in a chemically defined medium. The biological potency for promoting differentiation was dose-dependent for all the ligands with the highest potency displayed by IGF-I, followed by IGF-II, and the least ...

The initial response of the IGF-I system and the expression and cellular localization of IGF type-I receptor (IGF-IR) were studied in the gill of a euryhaline teleost during salinity acclimation. Exposure of striped bass (Morone saxatilis) to hyperosmotic and hypoosmotic challenges induced small, transitory (<24 h) deflections in hydromineral balance. Transfer from freshwater (FW) to seawater (...

Overexpression of the ErbB2 receptor in one-third of human breast cancers contributes to the transformation of epithelial cells and predicts poor prognosis for breast cancer patients. We report that the overexpression of ErbB2 inhibits IGF-I-induced MAPK signaling. IGF-I-induced MAPK phosphorylation and MAPK kinase activity are reduced in ErbB2 overexpressing MCF-7/HER2-18 cells relative to con...

analysis showed that this was a splice variant of the insulin-like growth factor-I (IGF-I) gene, although its 3 exons were different from the liver or systemic type of IGF-I. However, it was noted that muscle also expresses the systemic type of IGF-I (IGF-IEa). The terminology for the IGF-I variants is a problem when attempting to apply it to nonhepatic tissues and to different species. Also, w...

Insulin-like growth factor (IGF)-I is a critical protein for cell development and growth. Alternative splicing of the igf1 gene gives rise to multiple isoforms. In rodents, proIGF-IA and proIGF-IB have different carboxy-terminal extensions called the E-peptides (EA and EB) and upon further posttranslational processing, produce the identical mature IGF-I protein. Rodent EB has been reported to h...

We investigated the role of insulin-like growth factor (IGF)-I and IGF-binding proteins (IGFBPs) in the regulation of vascular endothelial growth factor (VE(ìF)expression in colon cancer cells and the mechanism by which this regulation occurs. HT29 human colon cancer cells were treated with K.I -I for various time periods. VEGF mRNA expression increased within 2 h and peaked at 24 h. SYV620 co...

The ontogeny of insulin-like growth factor-I (IGF-I) embryonic and extra-embryonic tissue concentrations were determined in the developing turkey embryo. At 2-d intervals, starting on Day 6 of incubation, individual tissues (n = 8 for each stage of incubation) were removed, weighed, pulverized, and extracted in 1 M acetic acid for IGF-I determination. Amniotic and allantoic fluid were collected...