THE PITUITARY BODY 



tains less gonadotropic hormone than the adult. However, 

 age seems to make no difference in the qualitative effects 

 (Siegmund and Mahnert, 1928; Lipschutz and Kallas, 1929). 

 The concentration of gonadotropic hormone in the pars 

 glandularis of rabbits about i month old is less than that in 

 rabbits more than 3 months old (assayed by the ovulation 

 test; Wolfe and Cleveland, 1931). The response of the ovary 

 of the rabbit in relation to age and weight is discussed in the 

 papers of Brindeau and others (1932), and Hertz and Hisaw 



(1934)- 



The sterility of male mice with hereditary dwarfism due to 

 changes in the pituitary can be corrected by the administra- 

 tion of implants of rat pituitary (Smith and MacDowell, 

 1930). In similar female mice after the same treatment, ir- 

 regular oestrous cycles as well as follicular growth and corpus 

 luteum formation in the ovary were observed. In the hairless 

 strain of rats studied by Emery (1935), the gonadotropic po- 

 tency of the pituitary seemed to be greater than that of nor- 

 mal albino rats provided that the same sexes were compared. 

 After spaying, however, the increase in the gonadotropic po- 

 tency of the pituitary of the albino female was greater than 

 that of the hairless female. (The oestrous cycles of the un- 

 operated hairless female were usually abnormal and often 

 absent.) 



The gonadotropic hormone{s) and ovogenesis. — According to 

 Swezy and Evans (1931) and Swezy (1933), ovogenesis does 

 not depend upon an internal secretion of the pars glandularis 

 of the pituitary. Gonadotropic extracts of the pituitary may, 

 however, play a part in regulating ovogenesis. 



The relation of the gonadotropic hormo?je{s) to compe?Jsatory 

 ovarian hypertrophy arid to the successful transplantation of the 

 ovary. — Engle (1928) administered homo-implants to nulli- 

 parous mice and rats (3-4 months old) from some of which 

 he had removed one ovary. As a result of this treatment, the 

 compensatory hypertrophy of the ovary was so great that, in 



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