Goat anti Human IGFBP5 polyclonal antibody [Biotin]

The mammary glands of dairy goats undergo physiological degeneration after peak lactation, resulting in a decline in milk yield. This phenomenon is closely related to mammary epithelial cells (MECs) apoptosis. The present study examined the expression levels of the insulin-like growth factor-binding protein-5 (IGFBP5) gene in the mammary tissues of dairy goats at various lactation stages and found that this gene was particularly highly expressed in the early and late lactation stages. In addition, the expression of IGFBP5 was assessed in different tissues from dairy goats in late lactation. IGFBP5 was expressed in various tissues, especially in the mammary glands. Overexpression of the IGFBP5 gene in vitro in cultured MECs from dairy goats inhibited the proliferation of the MECs and caused an increased in cell apoptosis. Western blot analysis of the proteins involved in the phosphoinositide-3-kinase (PI3K)/Akt signaling pathway revealed that overexpression of the IGFBP5 gene affected the PI3K/Akt signaling pathway, reduced the expression levels of PI3K and Akt, altered the balance between B -cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) and enhanced the expression level of the apoptosis-related protein caspase 3. The above results reveal that IGFBP5 is an essential regulatory factor in the growth of MECs. IGFBP5 inhibits the proliferation of MECs and promotes the apoptosis of MECs through the PI3K/Akt signaling pathway. (C) 2020 Friends Science Publishers

The insulin-like growth factors (IGFs) are essential for development; bioavailable lGF is tightly regulated by six related IGF-binding proteins (IGFBPs). Igfbp5 is the most conserved and is developmentally up-regulated in key lineages and pathologies; in vitro studies suggest that IGFBP-5 functions independently of lGF interaction. Genetic ablation of individual lgfbps has yielded limited phenotypes because of substantial compensation by remaining family members. Therefore, to reveal Igfbp5 actions in vivo, we generated lines of transgenic mice that ubiquitously overexpressed Igfbp5 from early development. Significantly increased neonatal mortality, reduced female fertility, whole-body growth inhibition, and retarded muscle development were observed in Igfbp5-overexpressing mice. The magnitude of the response in individual transgenic lines was positively correlated with Igfbp5 expression. Circulating IGFBIP-5 concentrations increased a maximum of only 4-fold, total and free IGH concentrations increased up to 2-fold, and IGFBP-5 was detected in high M-r complexes; however, no detectable decrease in the proportion of free IGH was observed. Thus, despite only modest changes in IGF and IGFBP concentrations, the Igfbp5-overexpressing mice displayed a phenotype more extreme than that observed for other Igfbp genetic models. Although growth retardation was obvious prenatally, maximal inhibition occurred postnatally before the onset of growth hormone-dependent growth, regardless of Igfbp5 expression level, revealing a period of sensitivity to IGFBIP-5 during this important stage of tissue programming.