THE PITUITARY BODY 



paralytic doses had been administered. After death as well as 

 under general anesthesia (ether, chloroform), the melano- 

 somes are said to be dispersed, but not completely. Oxygen 

 causes a concentration of the melanosomes; carbon dioxide 

 (in concentrations described as ''toxic") causes a dispersion 

 (Hewer, 1922; Uyeno, 1922). For experiments with other 

 drugs (guanidines, diuretics), see the reports of Ochoa (1928) 

 and Zieske (1932). 



The distribution in the pituitary body and in tissues and 

 body fluids oj the horfnone{s) causing dispersion of the melano- 

 somes or the erythrosomes. i. In the pituitary body. — The 

 melanosome-dispersing hormone can be detected in the 

 hypophysis of the ox-fetus and of the fetus of the sheep (both 

 at a fetal age of 3 months — Hogben and Crew, 1923); in the 

 hypophysis of the embryonic pig (crown-rump length of 30 

 mm. — Snyder, 1928); and in the hypophysis of the human 

 fetus (Ehrhardt, 1932). 



There is fairly complete evidence, which has been reviewed 

 already, that the pars intermedia of the amphibian pituitary 

 secretes the melanosome-dispersing hormone. The distribu- 

 tion of the hormone in the mammalian pituitary has chiefly 

 been studied in glands obtained from the ox and man. In con- 

 sidering the experimental data the reader should bear in 

 mind that Spaul (1927) found that the amount of the hor- 

 mone in the pars glandularis of the ox rapidly increased dur- 

 ing the first few hours after the removal of the pituitary. 

 This change was probably due to a rapid diffusion of the 

 hormone from the posterior lobe (pars intermedia). Hogben 

 and Winton (1922) performed their assays in the intact frog. 

 They concluded that the pars intermedia contained the most 

 (concentration) melanosome-dispersing hormone. The pars 

 glandularis contained the least amount. That present in the 

 pars neuralis was considered to have diffused from the pars 

 intermedia. Van Dyke (1926) controlled histologically the 

 dissected tissues (ox-pituitary) from which his extracts were 



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