330 



PHYSIOLOGY OF GONADS 



V 



vv 



#1. 



Fig. 5.12. Spermiogenesis in the monkey, i to 3 is the Golgi phase. 4 to 7 the cap phase, 

 8 to 12 the acrosome phase, and 13 to l-i the maturation phase. (From Y. Clermont and 

 C. P. Leblond, Am. J. Anat., 96, 229. 1955.) 



that in the bull. In the human, Leydig cells 

 are large polyhedral cells containing a large 

 vesicular nucleus, which is not found in 

 other cells of the interstitial tissue. The 

 cells contain pigment, vacuoles, crystalloids, 

 and granules. The granules vary in density, 

 number, and arrangement within the cyto- 

 plasm. These granules contain lipides (Nel- 

 son and Heller, 1945) and, like those in 

 common laboratory animals (Pollock, 

 1942), give reactions of steroids. Various 

 types of Leydig cells can be distinguished 

 on the basis of the size and nature of the 

 granules and vacuoles. The medium-sized 



granular cells are believed to be vigorous 

 producers of androgen (Sniff en, 1952; Til- 

 linger, Birke, Franksson and Plantin, 1955) . 

 It is difficult to determine the absolute num- 

 ber of Leydig cells. However, rough counts 

 made in testes of men (necropsy material) 

 indicate that the number declines with age 

 (Sargent and McDonald, 1948). In general, 

 the excretion of 17-ketosteroids and the de- 

 velopment and condition of secondary sex 

 characteristics parallel histologic and cyto- 

 logic evidence of secretory activity by the 

 Leydig cells (Fig. 5.15). 



It is generally held that the Leydig cell 



