Anatomy, Embryology, Comparative 



Anatomy, and Histology of the 



Endocrine Components 



of the Testis 



E. Y. COWDEY 



NEW YORK 



Anatomy 



The interstitial cells are scattered between the seminiferous tubules 

 and are often called the cells of Leydig, after their discoverer. Bearing, 

 in mind their possible glandular function, Bouin and Ancel (g) have ap- 

 plied to them the term of "Glande interstitielle du testicule." 



Interstitial cells are often grouped in a most suggestive way about the 

 blood vessels, as is illustrated in Fig. 1. No unusual relations have 

 been detected with lymphatics or nerve fibers. Assertions to the effect 

 that they are controlled by centers situated in the subthalamic region, or 

 elsewhere, are not very convincing in view of the success of transplants, 

 which would seem to indicate that, for the discharge of their duties, they 

 are not necessarily dependent upon the nervous system. 



Embryology 



According to Felix the interstitial cells develop very early, in embryos 

 of forty-five millimeters, as a differentiation of indifferent mesodermal 

 genitaloid cells, that is to say, before the formation of definitive germ 

 cells. These early interstitial cells may be identified by their large size 

 and pale nuclei, which are almost devoid of chromatin. After the fifth 

 month they apparently become quiescent, and formation ceases until after 

 puberty, when they appear in great numbers. They then undergo retro- 

 gression, only to increase again, but the reason for this later increase is 

 obscure and the observations of it require repetition. Even in extreme 



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