EFFFXTS OF EXTRACTS OF PARS NEURALIS 



the isolated pregnant human uterus; he concluded that the 

 changes in the oxytocin response throughout pregnancy- 

 resembled those in the uterus of the pregnant rabbit. Similar 

 variations in the uterine response to ergotoxine occurred. 



The response of the uterus of the rat and the guinea pig at 

 different times of the oestrous cycle or during pregnancy has 

 been investigated by Harne (1932) and Guidetti (1934)- 



Bourne and Burn (1928), who could use only impure 

 preparations of oestrin, found that these sensitized the iso- 

 lated guinea-pig uterus toward the oxytocic principle. Ap- 

 parently this effect was due to an impurity; for all subsequent 

 work (isolated uterus of ratj guinea pig, or rabbit) has shown 

 that oestrone, or oestriol, either antagonizes the effect of the 

 oxytocic principle or is without action (Siegert, 1931; Heller 

 and Holtz, 1932; Jeffcoate, 1932; Pompen and Gompaerts, 

 1932; Marrian and Newton, 1933; and Fomina, 1935). 



Klein and Klein (1933) used pregnant or pseudopregnant 

 rabbits. The injection of 2,500 rat-units of oestrin each day 

 did not abolish the oxytocin-insensitivity. Parkes (1930) 

 found that abortion followed a few hours after the injection, 

 into pregnant mice, of doses of both oestrin and oxytocin 

 which by themselves were without effect. ^According to 

 M0ller-Christensen (1934), the sensitivity of the uterus of 

 the immature guinea pig is increased -4-48 hours after the 

 administration of an enormous dose of oestrone (3,000 

 international units). 



2. The stomach and bowel. — Posterior-lobe extracts may 

 cause a diminution in the tone and movements of the 

 stomach in man (Schoendube and Kalk, 1925-26) and in the 

 dog (Quigley and Barnes, 1930). xA description of the effects 

 of the oxytocic and pressor principles on isolated strips of 

 the stomach of the cat and rabbit is given by Robson (193 1). 



The effects — if any — of posterior-lobe extracts on the 

 movements of the intestines appear to be due chiefly to the 



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