Figure 3

D-R relationships and time course for the phosphorylation response elicited by UTP or UDP on p44 and p42 MAPK. ( A) Phosphorylated isoforms of p44 (black dots) or p42 (white dots) were immunodetected (Western blot) in samples of theca cells that were stimulated with various UTP concentrations. The band intensities (OD) are expressed as a percent of the basal level, and the values were used to plot the D-R relationship. (B) Time course of the p44 and p42 phosphorylation process elicited by 10 μM UTP. (C) D-R for phosphorylation elicited by UDP in experiments similar to those in (A). (D) Time course of p44 and p42 phosphorylation elicited by 1 mM UDP. Data points are the mean ± S.E.M. of three independent experiments.