GONADS AND THE PITUITARY BODY 



vagina, and by oestral swelling of the uterus; such changes 

 are not produced in immature mice or rats after ovariectomy. 

 In addition, follicle growth in the ovary may be stimulated. '^ 

 Lipschiitz and his co-workers estimated that the amount of 

 pars glandularis required to produce some luteinization of the 

 ovary of the immature rat was about 10-15 times greater if 

 the anterior lobe was obtained from guinea pigs instead of 

 rats. To produce ovulation in the rabbit, 5 times as much 

 anterior lobe from guinea pigs as from rats was needed. The 

 amount of gonad-stimulating hormone in the pituitary of the 

 immature rat is approximately the same as that in the adult 

 rat (only the malei*); the pituitary of the immature guinea 

 pig, however, is said to contain less gonadotropic hormone 

 than that of the adult. The qualitative effects of implants of 

 the pars glandularis of the guinea pig are the same whether 

 the pituitary is obtained from male, female, or gonadecto- 

 mized guinea pigs. Lipschiitz believed that the anterior lobe of 

 this animal lacked a gonadotropic hormone necessary for the 

 growth and/or sensitization of the graafian follicle; provided 

 that follicular growth and/or sensitization was produced, 

 the anterior pituitary of the guinea pig then caused luteiniza- 

 tion (see the later discussion on the possible number of gon- 

 adotropic hormones). 



Homoplastic implants of the pituitary into immature 

 guinea pigs produce both growth and maturation of the 

 graafian follicle. Generally, ovulation and subsequent forma- 

 tion of true corpora lutea can be produced by homo-implants, 

 but not by implants or extracts of the pars glandularis of 

 other animals (Watrin, 1929; Loeb, 1932; and Aff and Loeb, 

 1934). According to Loeb and others (1932-34), implants or 

 extracts of the pituitary of the ox, sheep, and pig cause an 

 atresia of the follicles with luteinization of the theca interna, 

 whereas similar material from the rat, rabbit, and guinea pig 

 bring about growth and maturation of the follicles followed 



'5 Lipschiitz and others (1928, 1931-35), and Severinghaus (1932). 

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