ADRENALS 



669 



danger. . When injected intramuscularly, regular 1 and powerful con- 

 tractions of the uterus are excited in two or three minutes at any stage 

 in parturition. Another effect of extracts of the infundibular body is 

 on the mammary gland. An increased flow of milk follows the injec- 



Fig. 215. Action of Extract of Infundibular Lobe (Pars Nervosa of Ox Pituitary). 

 P, Carotid pressure; K, kidney volume; U, drops of urine; S, signal showing point 

 at which pituitary extract was injected; T, time- trace in zo-second intervals. 

 T is also the zero of the blood-pressure (Hering). 



tion of pituitrin (Simpson). But it is in doubt whether this is due to 

 increased secretion and not solely to stimulation of the smooth muscle 

 of the organ with expulsion of milk already formed. The depressor 

 substance produces a marked fall of blood-pressure, even when it is 

 injected during the rise of pressure caused by an injection of the pressor 



Fig. 216. Action of Extract of Hypophyseal Lobe of Pituitary on the Blood- Pressure 

 (W. W. Hamburger). The signal line at the top shows the time and length of 

 injection of the saline extract into the blood. Time-trace (at bottom) shows 

 second intervals. The figure is to be read from left to right. 



substance. The anterior lobe, or hypophysis, also contains a depressor 

 substance. Intravenous injection of a saline extract causes a distinct 

 fall of blood-pressure, accompanied usually by acceleration and weaken- 

 ing of the heart (Fig. 216). A second injection immediately following 

 the first produces no change in the pressure (W. W. Hamburger) . 



