THE PITUITARY BODY 



in rats on the first day of life, and the pituitary is removed on 

 the sixteenth to eighteenth day, the pituitary of the castrated 

 rat is about as potent as that of the spayed rat. However, if 

 the gonads are intact, the female pituitary is the more potent. 

 Moreover, castration changes in the pituitary can be found 

 in the male rat as early as the sixth day of life (castration on 

 the first day of life). These observations were made by Clark 

 (1935). It therefore appears that the internal secretion of the 

 testis is elaborated and liberated into the blood early in life; 

 the testis hormone lessens the secretion (or storage) of gonad- 

 otropic hormone in the pituitary (see the sections following 

 this). On the other hand, the hormone of the ovary^^ is not 

 secreted in appreciable amounts until the age of the rat is 

 greater than about 3 weeks. Therefore, the pituitary of the 

 very young female rat secretes (or stores) more gonadotropic 

 hormone and, in fact, is similar in this respect to the pituitary 

 of the castrated male. 



Lipschiitz (1933-34) beheved that the pituitary of the 

 adult female rat lacked a principle causing follicle growth or 

 sensitization. He suggested that the pituitary of the imma- 

 ture male or female rat as well as that of the adult male rat 

 contained this principle without which luteinization could not 

 occur. On the other hand, if this hypothetical substance was 

 supphed by also administering the urine of spayed women, 

 implants of the adult female rat pituitary then caused marked 

 luteinization. 



Experiments in animals living parabiotically; the bearing of 

 such experiments o?j the interrelationship of the gonads and the 

 anterior pituitary .^^ — The experiments were performed in rats 



^7 Reference here is made only to a hormone of the "oestrin" type. 



2^ For the discussion of experiments in this field, reference in this section is made 

 to the following authors: (i) Matsuyama (1921); (2) Yatsu (1921); (3) Goto (1924); 

 (4) Zacherl (1928); (5) Fels (1929); (6) Kallas (1929); (7) Martins (1930); (8) Mar- 

 tins and Rocha (1930); (9) Hill (1932); (10) Lower and Hicken (1932); (11) Witschi, 

 Levine, and Hill (1932); (12) Hill (1933); (13) Levine and Witschi (1933); (14) 

 Mj^ller-Christensen (1933); and (15) Witschi and Levine (1934). 



[144] 



