leuprolide and phorbolol-myristate-acetate

The receptor for gonadotropin-releasing hormone (GnRH) belongs to the G-protein-coupled receptors, and its stimulation activates extracellular signal-regulated protein kinase (ERK). In the present study, we first examined the actions of GnRH on the ErbB family using two types of cultured gonadotroph cells. As reported previously, AG1478, an inhibitor of the ErbB family tyrosine kinase, inhibited GnRH-induced ERK activation in undifferentiated gonadotroph αT3-1 cells. However, AG1478 did not inhibit ERK activation in differentiated gonadotroph LβT2 cells, suggesting that transactivation of the ErbB family was not necessary for ERK activation in LβT2 cells. We found that ErbB4 was expressed in αT3-1 cells but not in LβT2 cells. GnRH induced the cleavage of ErbB4 and accumulation of an 80-kDa fragment in αT3-1 cells. Pharmacological experiments suggested that G

Topics: ADAM17 Protein; Calcium-Calmodulin-Dependent Protein Kinases; Cell Line; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Gonadotrophs; Gonadotropin-Releasing Hormone; GTP-Binding Proteins; Leuprolide; Protein Kinase C; Proteolysis; Receptor, ErbB-4; Receptors, LHRH; Signal Transduction; Tetradecanoylphorbol Acetate