THE PITUITARY BODY 



rate was found to be reduced; also, there were enlargement 

 of the heart and hypertrophy of the ventricular wall. Because 

 of contraction of the vessels, the spleen was less than half the 

 normal size. The glomeruli of the kidneys resembled those 

 of hypertension in man. The profound peripheral vascular 

 disturbance apparently interfered with the growth of some 

 of the peripheral structures. Blount also had the impression 

 that the vascularity of the structures studied was increased 

 after hypophysectomy. 



All the other observations indicating that the cardiovascu- 

 lar effects of pars neuralis secretion may be physiologically 

 important have been made in mammals. Chang and his col- 

 leagues (1937) discovered that stimulation of the central end 

 of the vagus in the dog whose head is connected with the 

 body only by blood vessels, causes a rise in blood pressure re- 

 sembling that following the injection of vasopressor princi- 

 ple. The effect could be abolished either by hypophysectomy 

 or by cutting the pituitary stalk. Thus it appears that a re- 

 flex secretion of vasopressor principle can be demonstrated 

 in the dog. The vagus nerve is the only part of the afferent 

 arc known at present; probably the terminal efferent arc is 

 the supraoptico-hypophysial tract. The experiments of 

 Schockaert and Lambillon (1935-36), although of more de- 

 ductive significance, are also of considerable interest. They 

 showed that the serum of pregnant women seemed to bind 

 or inactivate, i.e., prevent, the vasopressor effect of a pars 

 neuralis extract in the decapitated cat. Later they demon- 

 strated that the intravenous injection of 5 units of a purified 

 solution of the vasopressor principle ("Tonephin") caused 

 much more severe symptoms such as precordial and abdomi- 

 nal pain, vomiting, and involuntary defecation in normal 

 women than in women in the last third of pregnancy. The 

 average elevation of the systolic blood pressure in non-preg- 

 nant women was 43 mm. Hg.'^ In the pregnant women, the 



" In spite of the recent statement of Gilman and Goodman (1937) that ". . . . in 

 unanesthetized dogs and humans, pituitary extract is not pressor," this observation 



[286 1 



