Posts Tagged ‘Rat

Our results also provide evidence that tyrosine phosphorylation is important in determining the effects of activin on Inh-a production. This follows from the observation that the PTK inhibitor tyrphostin A23 totally eliminates activin-induced increases in Inh-a mRNA and protein production. Tyrphostins are a family of synthetic PTK inhibitors that have been reported to block autophosphorylation […]

We present the first evidence that activin action can be inhibited by IGF binding proteins. Our data show that nanomolar concentrations of IGFBP-4 and -5 can totally inhibit the activin-dependent increase in Inh-a expression. The finding that IGF-I reversed the inhibition suggests that the mechanism of the IGFBP could involve a reduction in bio-available IGF […]

The main conclusion from these experiments is that endogenous IGF-I is required for activin-dependent stimulation of Inh-a expression in rat GC. The primary experimental evidence to support this conclusion is as follows. flovent inhaler

Reversibility of IGFBP-4 and -5 Inhibition To address the question of reversibility, we tested the ability of exogenously added IGF-I to counteract the inhibitory effects of IGFBP-4 and -5 on Inh-a production. As shown in Figure 4, cotreatment with increasing concentrations of IGF-I reversed the inhibitory effects of both IGFBP-4 and -5. At high IGF-I […]

Effects of IGFBPs and Anti-IGF-I Antibody on Inh-a Production To determine whether endogenous IGF-I is necessary for activin-stimulated Inh-a expression, we tested the effects of IGFBP-4 and -5, and an anti-IGF-I antibody on the activin response. As shown in Figure ЗА, the activin stimulation of Inh-a production was suppressed in a dose-dependent manner by cotreatment […]

Dose Response and Time Course of Activin Effects on lnh-а Expression We first investigated the dose response and time course relationships between activin and Inh-a production. Figure 1A shows that treatment with graded doses of activin for 48 h stimulated the production of 18-kDa Inh-a protein in a dose-dependent fashion (ED50 = 48.3 ± 6.7 […]

Western Ligand Blot Analysis Samples were prepared in nonreducing buffer, heated at 85°C for 3 min, and loaded onto a 14% Tris-glycine polyacrylamide gel. Electrophoresis and transfer were as described for Western immunoblot analysis. After transfer, detection was performed as described by Hossenlopp et al.. The nitrocellulose membrane was incubated overnight at 4°C with 400 […]