Immunolocalization of vascular endothelial growth factor in the GH₃ cell line

Abstract.

The question of whether vascular endothelial growth factor (VEGF) is expressed in the GH₃ cell line was investigated using immunocytochemistry, immunoelectron microscopy, and Western blotting. Using immunocytochemistry, VEGF was demonstrated in approximately 90% of the cells. Immunopositivity was localized mainly in the paranuclear Golgi region. In a small minority of cells, diffuse cytoplasmic immunostaining was also noted. By immunoelectron microscopy VEGF was evident in the secretory granules, cytoplasmic vesicles, rough endoplasmic reticulum, and the Golgi apparatus. Western blotting confirmed the results of the morphologic studies. It can be concluded that VEGF, which is know to induce angiogenesis and to increase vascular permeability, is produced in the prolactin- and growth hormone (GH)-secreting GH₃ cell line. The functional role of VEGF in the GH₃ cells is unknown. It is possible that this growth factor affects endocrine activity of GH₃ cells by a paracrine mechanism.