THE PITUITARY BODY 



Byrom was impressed by the analogy between the effects of 

 the vasopressor principle and the symptoms and pathology 

 of eclampsia. Later (1938), he observed that the prior in- 

 jection of oestrogen sensitized the rat toward the vasopressor 

 principle, so far as the production of eclampsia-like changes 

 in the kidneys are concerned. The author believed that this 

 later finding strengthens the view that the vasopressor hor- 

 mone is etiologically important in eclampsia. 



Several authors have published new reports on the action 

 of posterior-lobe extract or of purified vasopressor principle 

 on the medulla^ If 5-10 units be injected intracisternally 

 into the dog, a pressor effect immediately appears, probably 

 because of stimulation of bulbar centers such as the vaso- 

 motor center. In comparison with intravenous injection, (i) 

 the pressor effect is less pronounced but persists longer in 

 terms of the rise in blood pressure and (2) a preliminary fall 

 (coronary constriction) is not observed. It is probable that 

 the effects cannot be attributed to the absorption of the hor- 

 mone into the blood stream. 



In the experiments of Daly, Mark, and Petrovskaia (1937) 

 posterior pituitary extracts were added to the blood used 

 to perfuse the lungs of dogs. A suitable period later it was 

 found that there was a reversal of the usual action of epineph- 

 rine on the bronchi — i.e., broncho-constriction instead of 

 broncho-dilatation was produced. This effect was prevented 

 by ergotoxine. The extracts, of which "Pitocin" appeared 

 the least active and "Pituitrin" the most active, also poten- 

 tiated the action of epinephrine on the vascular system of the 

 lungs. 



Among new observations on the effects of posterior-lobe 

 extracts on the eye are those of Holtz and Jancke (1936). 

 Only the vasopressor principle was found to cause definite 

 changes. For example, the instillation or subconjunctival in- 

 jection of a large dose of the hormone (10 units) caused a 



7 Van Bogaert, Sacchi (1935); Deleonardi, Seligsohn (1936). 



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