FIG. 1.
Effect of rosiglitazone (Rosi) on GnRH-induced activation of p38MAPKs, JNKs, and ERKs. LβT2 cells (1.5 × 106 cells/well) were treated with rosiglitazone (10 μM) or DMSO as vehicle for the indicated time periods. After 0, 24, or 48 h of pretreatment with rosiglitazone, the cells were incubated in serum-free DMEM containing 0.1% BSA for 24 h before treatment with varied concentrations of GnRH (0, 0.01, 0.1, 1, 10, or 100 nM) for 30 min. Whole-cell lysates were separated on SDS-PAGE and immunoblotted with an antibody for phospho-p38MAPKs (p-p38), phospho-JNKs (p-JNK), and phospho-ERKs (p-ERK; A). The blots were stripped and reblotted for p38MAPKs, JNKs, or ERKs, respectively, to determine the total protein loading. The blots are representative experiments, each repeated three times. Quantification of the GnRH dose response in the presence of rosiglitazone is also shown (B). Sigmoidal dose-response curves were modeled and tested for significance. Rosiglitazone caused a statistically significant decrease in the dose-response curve for p38MAPK and JNK activation by GnRH (P < 0.05) and a significant increase in the dose-response curve for ERK activation (P < 0.05).