Fine structural cytology and immunohistochemistry of the non-adenomatous pars distalis of the human pituitary

Abstract

The ultrastructural features and immunohistochemical characteristics of nontumorous adenohypophysial cells in the human pituitary are briefly reviewed and the usefulness of electron microscopy and immunoelectron microscopy is stressed in cell identification. Recent immunoelectron microscopic studies demonstrate the presence of plurihormonal cells containing more than one hormone, not only in pituitary adenomas but also in nontumorous adenohypophyses. These results lead to the conclusion that the one cell- one hormone theory, which dominated pituitary cytophysiology and cytopathology for several decades, is untenable.