Fig. 5.
The GHR antagonist monoclonal antibody, anti-GHRext-mAb, inhibits GH-induced signaling in T47D-ShPRLR, but not T47D-SCR, cells. A and B, Serum-starved T47D-SCR vs. T47D-ShPRLR cells were pretreated with or without anti-GHRext-mAb for 15 min before treatment with GH (100 ng/ml) or vehicle for 10 min. Detergent cell extracts were resolved by SDS-PAGE and sequentially immunoblotted with anti-pSTAT5 and anti-STAT5 (A). B, Densitometric analysis of data from three separate experiments, performed as in A, was used to estimate pSTAT5 levels. For each experiment, the pSTAT5 level achieved in response to 100 ng/ml GH in T47D-ShPRLR cells in the absence of antibody pretreatment was considered 100%. Data are expressed as mean ± S.E. for each GH concentration relative to 100%. pSTAT5, Phosphorylated STAT5.