PARS GLANDULARIS AND LACTATION 



growth of alveoli appears to depend to an important extent 

 on the action of progesterone, although this may not be true 

 of other mammals, e.g., the guinea pig. Gardner, Gomez, and 

 Turner (1935) produced mammary development in normal 

 male rabbits or in normal or spayed (multiparous) female 

 rabbits by injecting 20-25 rat-units of oestrone daily for 

 about 3 weeks. If lactogenic hormone was injected within not 

 more than 3 days after oestrone treatment was stopped, lac- 

 tation promptly appeared. The observations of others who 

 used rabbits do not require a detailed description.'' Similar 

 experiments have been performed in castrated male rabbits. 

 In the normal monkey (xAllen, Gardner, and Hill, 1935) and 

 in the goat (De Fremery, 1936) the administration of an oes- 

 trogen will likewise suitably prepare the mammary gland so 

 that lactogenic hormone is then effective. Gardner (1935) 

 produced general development of the duct system, as well as 

 some localized growth of alveoli in male mice with ovarian 

 grafts in the testis. In the depancreatized bitch treated with 

 insulin, lactogenic hormone produces lactation, provided that 

 mammary development corresponds to that of pregnancy or 

 pseudopregnancy (Nelson, Himwich, and Fazekas, 1936). 

 Houssay (1935) used only an oestrogen to bring about mam- 

 mary development in normal or gonadectomized dogs of both 

 sexes ("folliculin" as 1,000-10,000 international units daily 

 for 49-90 days). The intraperitoneal administration of what 

 was probably a crude extract of beef anterior lobe then 

 caused lactation. ^ 



Certain experiments in the mouse, rat, and guinea pig are 

 of particular interest because they indicate that mammary 

 development following the administration of an oestrogen 

 cannot take place in the absence of the pituitary body.^ 



•< Anselmino, Herold, and Hoffmann (1935), Macdonald (1936), Margulis (1936), 

 Fallot (1936), and Gillard (1937). 



5 The effects were present after removal of the lumbar sympathetic chains. 



^Houssay stated that the pituitary is not necessary in the dog. Nelson (1935^ 

 reported that oestrone produced about the same degree of mammary development in 

 male guinea pigs, whether or not the pituitary had been removed. Also, Asdell and 



[153] 



