332 



PHYSIOLOGY OF GONADS 



Numbers 



of 



Leijdigl 



cells 



Fig. 5.15. Schematic summary of thv life history of the human Leydig cell. (From A. 

 Albert, L. O. Underdahl, L. F. Greene, and N. Lorenz. Proc. Staff Meet., Mayo Clin., 29, 

 368, 1953; 30, 31, 1955.) 



is the source of androgen. Gonadotrophin 

 evokes secretion of androgen from the testis 

 only if the Leydig cells are stimulated. 

 Tumors of Leydig cells produce large 

 amounts of androgen. Testes impaired by 

 heat or x-rays still produce androgen even 

 though the germinal epithelium may be 

 destroyed. The parallelism between the 

 number of Leydig cells, their morphology, 

 histologic appearance, and histochemical 

 properties (Wislocki, 1949), on the one 

 hand, and androgenic secretion as measured 

 chemically or as determined by the be- 

 havior of the secondary sex characteristics, 

 on the other hand, supports the conclusion 

 that the Leydig cell produces male hor- 

 mone (Figs. 5.16 and 5.17). 



XI. Hormones of the Testis 



The mammalian testis produces andro- 

 gens and estrogens. Because the chemistry 

 of the hormones is discussed in Villee's 

 chapter, only a brief account will be given 

 here. Testosterone was first obtained from 

 bull testes and later from horse testes (Tag- 

 mann, Prelog and Ruzieka, 1946). However, 

 difficulties attended the isolation of tes- 

 tosterone from the testes of pigs. Although 

 not obtained in crystalline form, testos- 

 terone was identified bv a characteristic in- 



frared absorption spectrum in extracts of 

 hog testes (Prelog, Tagmann, Lieberman 

 and Ruzieka, 1947). Other steroids are 

 present in hog testes (Ruzieka and Prelog, 

 1943; Prelog and his associates, 1947). C21- 

 ketosteroids, such as allopregnane-3-(^)- 

 ol-20-one, allopregnane-3- (a) -ol-20-one, 

 and 5-pregnane-3-(^)-ol-20-one, have 

 been identified. Haines, Johnson, Goodwin 

 and Kuizenga (1948) isolated pregnenino- 

 lone from hog testes as well as several other 

 unidentified steroids, some of which had 

 estrogenic activity. Ketosteroids have been 

 found in human sperm (Dirschcrl and 

 Breuer, 1955). 



The testes of deer, bulls, stallions, and 

 humans contain estrogens. The amount 

 present in deer testes is three times that in 

 bulls (Cunningham, ]\Iay and Gordon, 

 1942). Estradiol (0.21 mg. per kg. I and 

 estrone (0.36 mg. per kg. ) wer(> isolated 

 from 28 kg. of hoarse testes by Beall 1 1940). 

 Estradiol also has been isolated from hinnan 

 testes obtained shortly after death (Gold- 

 zieher and Roberts, 1952). 



Testicular tissue is able to convert ace- 

 tate into cholesterol (Srere, Chaikoff, Treit- 

 man and Burstein, 1950) and also to testos- 

 terone in the hog, rat. and human (Brady, 

 1951). Human chorionic gonadotrophin 



