Insulin-like growth factor type 1 receptor and insulin receptor isoform expression and signaling in mammary epithelial cells.

ABSTRACT: The insulin receptor (IR) isoforms and the IGF type 1 receptor (IGF-1R) share a high degree of structural homology but differ in ligand binding kinetics and functions. We developed a highly specific quantitative PCR assay to quantify and compare IR-A, IR-B, and IGF-1R expression within an RNA population. We determined receptor expression in primary murine mammary epithelial cells (MECs) during postnatal development. Both IR isoform mRNAs were 3- to 16-fold higher than IGF-1R expression at all developmental times. IR protein was also 3- to 10-fold higher than IGF-1R protein; however, significantly less IGF-1R was found in hybrid receptors at early (49%) vs. late (79%) pregnancy, indicating that the amount of hybrid receptor is developmentally regulated. Despite high IR expression, IGF ligan

SUBMITTER: Rowzee AM 

PROVIDER: S-EPMC2717875 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature