Immunocytochemical localization of basic fibroblast growth factor in the human pituitary gland

The immunocytochemical localization of basic fibroblast growth factor (bFGF) was studied in the human pituitary gland using a polyclonal antibody against fraction 1-24 of bovine recombinant bFGF. From a technical perspective, methacarn-fixed tissues were associated with a better preservation of bFGF immunoreactivity. Basic FGF-immunopositive glandular secretory cells were detected from the fetal period to adulthood in the pars distalis. No bFGF-positive cells were found in the neural lobe, basophil invasion areas, pars tuberalis or the walls of the pituitary cleft in the fetal pituitaries where this area was available. Endothelial cells and the axons of the neurohypophysis appeared weakly immunopositive or immunonegative depending on the fixative. According to their morphology, distribution, and the serial section analysis with all the pituitary hormones and vimentin, a folliculostellate cell marker, we conclude that bFGF-positive cells appear to be somatotropes. These results are consistent with the interpretation that bFGF plays a paracrine role in the modulation of the synthesis and secretion of various pituitary hormones.