HYPOPHYSEAL MORPHOLOGY 



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Fig. 3.26. Electron micrograph showing cells from the anterior pituitary of a young adult 

 male rat. Three acidophils of the type which are thought to be responsible for the production 

 of growth hormone (Hedinger and Farquhar, 1957; Farciuhar and Rinehart, 1954a) occupy 

 most of the field. Their nuclei (AO are indicated. 



This type of acidophil is characteristically rounded or ovoid in shape, and the cells typically 

 are arranged in groups, as shown here. In electron micrographs the most distinctive feature 

 is their content of variable numbers of dense, ovoid secretory granules (grr) of a characteristic 

 size (ca. 350 ni/u maximal diameter). Large numbers of secretory granules are present in this 

 field. The cell membranes {cm) can be clearly seen separating the cytoplasm of one cell from 

 that of another. Mitochondria (m), endoplasmic reticulum (er), and Golgi material (G) may 

 also be distinguished. X 10,300. 



is termed "the negative image of the Golgi 

 body." The negative image of the Golgi 

 body or zone is especially conspicuous in 

 the basophil cells of the rat pars anterior. 

 In acidophil cells the Golgi body is usually 

 smaller and the negative image is not seen 

 unless the sections are thin, i.e., 2 to 3|U.. 

 When acidophil cells are stimulated their 

 Golgi zones become enlarged and the nega- 



tive image may be seen more easily. This 

 happens in the rat hypophysis after estrogen 

 treatment or at times when rapid secretion 

 of the lactogenic hormone is occurring phys- 

 iologically. The Golgi region has the ap- 

 pearance of a spheroidal shell enclosing an 

 area of cytoplasm. In the basophil cells of 

 the rat pituitary, the cytoplasm enclosed by 

 the Golgi region is more deeply stained than 



