FIGURE 5.
Inhibition of ERK-mediated feedback impairs GnRH sensing. Panel A shows population-averaged ppERK2 levels after knockdown of endogenous ERK and add-back with Ad ERK2-GFP or Ad K52R ERK2-GFP before stimulation for 5, 10, 20, or 60 min with GnRH (0 or 10−12–10−6 m). Cells were fixed and stained (DAPI and ppERK), and the single cell ppERK measures were used to calculate the I(ppERK2;GnRH) values in panel B. The data are from three separate experiments each with triplicate wells and three fields of view per well. Two way ANOVAs of the ppERK2 measures (A) revealed significant differences between ERK2- and K52R ERK2-expressing cells (at all times). Similar ANOVAs of the MI measures (B) revealed a significant difference between ERK2- and K52R ERK2-expressing cells (p < 0.01) and post hoc Bonferroni tests revealed significant differences at 5, 10, and 20 min (**, p < 0.01). These data are from a series of experiments performed in parallel with those shown in Fig. 1.