Immunoelectron microscopic evidence of mammosomatotrophs in human adult and fetal adenohypophyses, rat adenohypophyses and human and rat pituitary adenomas.

Immunoelectron microscopy, utilizing the double labelling immunogold technique, revealed the presence of mammosomatotrophs in human adult and fetal rat adult adenohypophyses as well as human and rat pituitary adenomas. These cells are characterized by the coexistence of GH and PRL not only in the same cells but also in the same secretory granules.