THE PITUITARY BODY 



tered intraperitoneally, seem to prevent or lessen the ovarian 

 changes caused by injecting prolan into immature rats. 



If prolan is repeatedly administered over a period of 

 weeks or months, the ovarian changes in injected rats gradu- 

 ally disappear until no hypertrophy or even some atrophy is 

 found (Selye, Collip, and Thomson, 1934). Similarly, prolan 

 causes ovulation in rabbits less frequently if it has already 

 been injected thrice previously (Hill, Parkes, and White, 

 1934). Again, Wade (1933) was able to cause the transfor- 

 mation of "wheel" cells into lutein-like cells in the ovaries of 

 hypophysectomized rats by injecting prolan, but not if the 

 rats had received prolan 2 or 3 weeks previously. To explain 

 facts like these, Selye, Bachman, Thomson, and Collip 

 (1934) have postulated the production of an "antihormone" 

 which they detected biologically in the blood of animals given 

 a long course of injections of prolan. Even 70 days after in- 

 jections had been stopped, sera still prevented gonad stimu- 

 lation by prolan in immature rats; the serum of gonadecto- 

 mized rats which had received a series of prolan injections 

 also contained "antihormone" (Bachman, Collip, and Selye, 

 1934)- 



PROLAN AND OTHER GLANDS OF INTERNAL SECRETION 



Prolan and the pituitary body. — In studies of the effect of 

 prolan on the anterior pituitary in rats, the usual findings 

 are as follows: (i) hypertrophy of the anterior pituitary oc- 

 curs in female animals but not in males; (2) this hypertrophy 

 does not occur in spayed or very young females; and (3) the 

 gonadotropic potency of the pituitary is reduced in both 

 male and female animals which have received prolan. Some 

 of these facts are interpreted by Collip, Selye, and Thomson 

 (1933), and Bergmann (1934) as indicating that gonad 

 stimulation by prolan in the female requires the participation 

 of the anterior pituitary, whereas in the male, Leydig's cells 

 are directly stimulated. The anatomical changes, also re- 



[214I 



