THE  AMEEIOAN 
JOURNAL  OF  P  H ASKMA 0 Y 
From  the  Division  of  Pharmacology,  Leland  Stanford  Jr.  University. 
After  having  discovered  the  pressor  action  of  the  extracts  of  the 
adrenal  glands,  Oliver  and  Schaefer  1  studied  the  action  of  those 
made  from  other  ductless  glands.  They  found  that  aqueous  or 
glycerine  extracts  of  sheep  pituitaries,  on  intravenous  injection  into 
certain  animals,  caused  a  persistent  rise  in  blood-pressure,  usually, 
but  not  always,  associated  with  a  slowed  heart-rate.  This  rise  oc- 
curred even  in  animals  with  the  medulla  destroyed,  and  perfusion 
experiments  proved  the  action  to  be  mainly  peripheral.  An  increase 
in  the  force  of  the  heart  action  is  partly  responsible  for  this  rise, 
as  extracts  of  pituitary  glands  act  directly  on  the  muscle-fibres  of 
the  vessels  and  heart.  The  pressor  action  is  especially  marked  in 
cases  of  artificially  lowered  blood-pressure. 
The  few  experiments  which  Szymonowicz  2  made  suggested  that 
extracts  of  this  organ  caused  a  fall  in  blood-pressure  with  a  rapid 
heart-beat,  the  opposite  condition  to  what  Oliver  and  Schaefer 
found.  Silvestrini 3  merely  noted  a  fall  in  blood-pressure,  and  this 
seemed  to  be  the  characteristic  reaction.  According  to  von  Cyon, 
there  are  two  compounds :  one  which  slows  and  strengthens  the 
1  Oliver,  G.,  and  Schaefer,  E.  A.,  "  On  the  Physiological  Action  of  Ex- 
tracts of' Pituitary  Body,"  Jour,  of  Physiology,  vol.  18,  p.  277  (1895). 
2  Szymonowicz,  L.,  "  Die  Function  der  Nebennieren,"  Archiv.  f.  Physiol, 
vol.  64,  p.  131  (1896). 
3  Silvestrini,  R.,  "  Sull'  azione  dell'  estratto  aquoso  del  lobo  posteriore  dell' 
ipofisi  sulla  pressione  sanguinea,"  Rcvista  critica  di  din.  mcd.,  No.  28,  1905, 
seen  only  in  reference. 
CONTRIBUTION  TO  THE  CHE^&|^Y  ^\%HE 
PITUITARY  PRESSOR  COMPtTTO^>5^' 
By  Albert  C.  Crawford  and  Zeno  Ostenberg, 
1291) 
