Ultrastructure of the Normal Pituitary

Abstract

The first important step in differentiation of the adenohypophysial cell types was made by Schönemann (1892). He described eosinophilic, cyanophilic (basophilic), and chromophobe elements. The system of three cell types was used with minor modifications until Romeis (1940) published his fundamental study concerning the histology of the pituitary gland. He counted five different granulated, one undifferentiated, and one vacuolated, exhausted cell types. Pathologists and clinicans have continued to use the old, three cell type system in spite of these new histological results. This mainly was due to the fact that the “kresazan-method” of Romeis was quite capricious and produced unreliable results in unskilled hands. A large variety of fixation and staining methods was developed because of these difficulties (for review see Herlant, 1964; Purves, 1966). Most of these methods were used in different laboratory animals. The use of an almost endless variety of such techniques made the comparison of the results of different authors extremely difficult. Moreover, in some species a certain fixation and staining method may make it possible to distinguish between certain cell types, whereas the same technique may fail to show these cell types in other species.