THE PITUITARY BODY 



it is commonly made from tissue containing the pars inter- 

 media and because the hormone readily diffuses into it and 

 into other parts of the pituitary body. It is interesting that 

 Lewis and his colleagues could furnish no support for the 

 view, which has been popular with some European authors, 

 that chromatosome-dispersing hormone may be secreted by 

 way of the stalk into the cerebrospinal fluid. 



The chromatosome-dispersing hormone is secreted by cells 

 of the pars buccalis. In animals in which the pars intermedia 

 can be identified morphologically there can be little doubt 

 that that division of the pars buccalis secretes the hormone. 

 In animals like the whale in which no pars intermedia can 

 be found, the hormone can be extracted from the pars glandu- 

 laris (Geiling, 1935). Fisher (1937) reported that in the pos- 

 terior lobe of the pituitary of cats in which marked atrophy 

 of the pars neuralis had been produced experimentally, there 

 appeared to be no reduction in the amount of chromatosome- 

 dispersing hormone as determined by the response of the 

 melanophores of frogs or the erythrophores of the red-bellied 

 dace {Chrosomus erythrogaster)^^ The atrophied pars neuralis 

 contained no oxytocic or vasopressor (and diuresis-inhibiting) 

 hormone. The results of Geiling and Lewis (1935) also in- 

 dicated that the pars intermedia is the site of formation of 

 the chromatosome-dispersing hormone. The authors under- 

 took to make tissue cultures of the pars glandularis, the pars 

 intermedia, or the pars neuralis of the mouse and rat. The 

 pituitary of the mouse was preferred as a source of the tissues 

 because the various divisions could be separated more com- 

 pletely. After culture for 50 days, the pars intermedia con- 

 tained chromatosome-dispersing hormone but no vasopressor 

 hormone, indicating that the latter is not secreted by the 

 pars intermedia. Both hormones could be detected in cul- 

 tures of the pars neuralis not entirely free from pars inter- 



'■5 Fisher was not satisfied that accurate results could be obtained by the use of 

 this fish, 



[ ^-54 ] 



