EFFECTS OF EXTRACTS OF PARS NEURALIS 



true vasopressor principle or to an unidentified principle is 

 not known, '5 Houssay and Di Benedetto (1933) reported on 

 the relationship between the dose of a posterior-lobe extract 

 and the hyperglycemic effect. They made intravenous in- 

 jections of the diluted extract into dogs. 



In antagonizing the hypoglycemic effect of insulin pos- 

 terior-lobe extract has a moderate but well-sustained effect. 

 The antagonism is greater than would be expected from the 

 moderate hyperglycemia which follows the injection of the 

 extract into normal animals (Burn, 1923; Voegthn, Thomp- 

 son, and Dyer, 1925; Heymans and Pupco, 1926; and others). 

 Under conditions in which severe symptoms of hypoglycemia 

 appear, the injection of posterior-lobe extract mav abolish a 

 part or all the symptoms without altering significantly the 

 concentration of sugar in the blood (venous?) (Cassidy, 

 Dworkin, and Finney, 1926; Gelling, Britton, and Calvery, 

 1929). Perhaps in such experiments the blood-sugar concen- 

 tration is increased only in the arterial blood. '^ Also, in op- 

 position to the effect of insulin, posterior-lobe extract or the 

 vasopressor principle causes an elevation in the concentra- 

 tion of inorganic phosphate in the blood (Niitsu, 1930; 

 Gelling and others, 1931). Lambie and Redhead (1929) 

 observed this effect in the rabbit but not in man.'^ 



An increase in the concentration of lactic acid in the blood 

 is said characteristically to occur after the injection of large 



'5 Burn (1928); Gelling and Eddy (1928); Himwich and others (1928, 1932); 

 Elmer and Scheps (1930); Gavrila and Mihaileanu (1930); Nitzescu and Benetato 

 (1930); Geiling and others (1931); Hynd and Rotter (1932); Schroeder (1933); 

 Thaddea (1933); Thaddea and Waly (1933); and Mclntyre (1934). 



Houssay and Magenta (1929) as well as Holman and Ellsworth (1935) believed 

 that the oxytocic principle is the more effective. 



'^ Geiling, De Lawder, and Rosenfeld (1931) found that the hyperglycemia due 

 to posterior-lobe extract initially was much greater in arterial in comparison with 

 venous blood. 



" Insulin has been found to antagonize the diuresis-inhibiting effect of posterior- 

 lobe extract (Klissiunis, 1925; Serebrijski and Vollmer, 1925; and Koref and Maut- 

 ner, 1926). 



[361] 



