THE MALE HORMONE 



dence that testosterone, or something very much like it, is in 

 circulation in the body. 



Just what cells in the testis are responsible for producing 

 the hormone is an interesting and debatable question. There 

 are two possibilities, the interstitial cells on one hand, and 

 the spermatogenic cells of the tubules on the other. Let us 

 examine the evidence. In the first place the interstitial cells 

 look like endocrine tissue, since they are large cells provided 

 with a rich circulation of blood but obviously not producing 

 an external secretion, for they are not arranged in channels 

 and ducts. Years ago, moreover, Bouin and Ancel called 

 attention to evidence favoring the interstitial cells as the 

 source of the hormone. When the testes fail to descend and 

 therefore do not form sperm cells, the cells lining the tubules 

 are reduced to an inactive state (Plate XXIV, B). They 

 assume a vague, nondescript form as if they were merely 

 surviving without any function. The interstitial cells however 

 remain in place, they look normal, and indeed have even been 

 thought to increase in amount. Although the cryptorchid 

 animal or man bearing such sex glands is sterile, he develops 

 male secondary sexual characters and male sex psychology. 

 With the spermatogenic cells seemingly inactive (as judged 

 by appearances under the microscope) but the interstitial 

 cells in good condition, it is difficult to avoid the assumption 

 that the latter are making the sex hormone. When bits of the 

 testis are grafted successfully into a castrated animal the 

 same cellular state develops in the grafts, and the animal 

 likewise develops male qualities. It was formerly thought that 

 tying off the seminal ducts produced the same effect. The 

 Steinach operation described above was based upon this whole 

 set of considerations. It is now known, however, that blocking 

 the ducts and thus damming up the semen does not stop 

 spermatogenesis. It is also known that cryptorchid (unde- 

 scended) testes with inactive sperm cell formation do not 



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