CHAPTER X 



THE PARS NEURALIS AS A GLAND OF 

 INTERNAL SECRETION 



THE belief that the pars neuralis is an important 

 gland of internal secretion has been greatly strength- 

 ened by recent experimental work on the physiologi- 

 cal importance of the diuresis-inhibiting (or vasopressor) 

 principle, confirming the earlier views of Starling and Verney, 

 to mention only two of many investigators. Some of the re- 

 ported experiments also indicate that secretion(s) of the pars 

 glandularis is responsible or necessary for the marked poly- 

 uria and polydipsia accompanying the suppression of pars 

 neuralis secretion. On the other hand, the importance of a 

 secretion of the oxytocic principle has not yet been demon- 

 strated and no data of great significance have been added to 

 those previously reviewed. To a less extent this is also true 

 of the possibly important vascular effects of the vasopressor 

 principle. 



Recent attempts to detect the active principles of the pars 

 neuralis in cerebrospinal fluid or blood. New studies of the 

 principles in the pituitary body. — Attempts to detect the ac- 

 tive principles of the pars neuralis in cerebrospinal fluid have 

 not met with convincing success. In a recent report Deleo- 

 nardi (1936) concluded that oxytocic, pressor, and diuresis- 

 inhibiting effects can be produced both by the cisternal fluid 

 of the dog and rabbit and by the ventricular fluid (second and 

 third ventricles) of the human cadaver but only exception- 

 ally by human lumbar fluid. His observations on the oxytocic 

 and pressor effects were not adequately controlled, because 

 he failed to take into account the oxytocic efl'ect of calcium 

 ions in cerebrospinal fluid (he mentions that he employed a 

 Tyrode's solution low in calcium for the uterine bath) and 



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