Electron Microscope Studies on the Secretory Cytology of the Mouse Anterior Pituitary1

Abstract

The secretory cytology of mouse anterior pituitary has been investigated by means of electron microscopy, controlled by light microscope procedures. The material examined included: tissue from animals in various normal functional states, and from animals which had been castrated. Five morphologically distinct and easily recognized varieties of secretory cells are present in mouse pituitary tissue. The fine structure of each variety is described and illustrated. Provisional functional identities have been assigned to these 5 cellular classes by studying their respective reactions to functional change. It is suggested that 5 of the 6 known anterior pituitary hormones (GH, LTH, TSH, LH and FSH) are produced by these 5 classes of cells. In light microscope studies, a group of cells homogeneous with respect to a particular staining affinity may well not be homogeneous with respect to function. The results of the present study suggest that each of the 5 groups of cells, identified in the electron microscope on the basis of morphologic characteristics, constitutes a functionally homogeneous group of cells.