218 



HYPOPHYSIS AND GONADOTROPHIC HORMONES 



/ 



cm 



N 



nc 



i'l»ViiiJ^»>^ 







l^li -."*#'i§fc'^^5#ff. 



Fig. 3.29. Electron microgmph allowing a \li>- Lugr guu:uloii(ii>li iium iln ,1111(1101 

 pituitary of a young adult male rat. The nucleus (iV), a nucleolus {nc), and the cell membrane 

 {cm) are shown. 



This cell can be identified as a gonadotroph by virtue of its rounded contours and content 

 of secretory granules {gr) with a maximal diameter of approximately 150 m^. The secretory 

 granules of gonadotrophs are intermediate in size between the large secretory granules of 

 acidophils and the small secretorj^ granules of thyrotrophs. 



A spherical chain of small vacuoles {vac) circumscribes the Golgi apparatus which is 

 located above the nucleus. Elements of the Golgi complex outline a cytoplasmic area nearlv 

 as large as the nucleus. 



Mitochondria (m) which have been sectioned in various planes are also visil)l(> in the 

 cytoplasm. The mitochondria of gonadotrophs are generally more elongated and show a 

 denser internal background matrix than other types of adenohypophyseal cells. 



The endoplasmic reticulum {er) is seen here in the form of numerous vesicles which vaiy 

 greatly in size. Some are relatively small and are of a size approaching that of the secretory 

 granules. Others are rather large, for they measure several microns across at their greatest 

 width. It can be seen that the intermmi of the vesicles appears homogeneously grey, and has 

 a background density greater than that of the siuTOunding cytoplasmic matrix. 



Gonadotrophs with this appearance have been associated with the secretion of follicle- 

 stimulating hormone (Farquhar and Rinehart, 1954a: Farduhar and Rinehart, 1955). They 

 differ from the luteinizing hormone-gonadotroph (see Fig. 3.30) in possessing somewhat 

 paler nuclei, more evenly distributed granules, and prominent vesicles of the endoplasmic 

 reticulum with the homogeneous grey internum. X 6500. 



