XI. PFlAKMAfOLOfiY 55 



found (lopres-sion of <2;ro\vtli in young rats injected inliapciiloiically with 

 only 7.5 niji". daily for IS day.s. Marked accumulation of intestinal jj;a.^ 

 occurred, alonp; with diarriiea. Young luunan patient.s who receix'ed up to 

 148 g. of PAH.V ovcv a jieriod of days in treatment of acute rhcninatic 

 f(^ver on autopsy showed deposits of fat in epithelial cells of li\'er, kidney, 

 and myocardium, according to Cruickshank and Mitciiell.-"' These authors 

 noted similar changes in rabbits. 



It is oln'ious from the above that the toxicity- of PABA is relatively of 

 a very low grade, either in acute or chronic administration. 



C. PHARMACOLOGICAL ACTIONS 

 1. Circulatory System 



Like procaine, intravenous injection of PABA reduced the incidence of 

 ventricular fibrillation induced by epinephrine in dogs under cyclopropane 

 anesthesia.^" 



According to (libbs and Hare,^^ PABA given intravenously in doses of 

 0.5 to I g. per 8 kg. had no effect on pulse rate or blood pressure of dogs. 

 This was confirmed by Richards,-^ who noted only slight elevation of blood 

 pressure of dogs or cats injected intravenously with doses of 100 mg. per 

 kilogram. 



2. Blood 



PABA was found to increase blood and tissue iron of liver and muscle 

 of rabbits treated simultaneously with reduced iron.^' Likewise, Annoni^- 

 found that certain cases of anemia responded to PABA, with a rise of 

 hemoglobin level amounting to 8 to 12% and a small increase of red blood 

 cells. PABA was capable of restoring prothrombin time to normal when 

 depressed by sodium salicylate.^' 



3. Gastrointestinal Tract 



Baldini and Cer^^' '' reported that PABA temporarily stimulated gastric 

 motility and gastric secretion Init had no ellect on gastric acidity of hu- 

 mans. Merlo and Ercoli'^ confirmed the gastric secretory effect except in 



29 A. H. Cruickslmnk and G. W. Mitchell, Jr., Bull. Johns Hopkins Hosp. 88, 211 



(1951). 

 ^" B. A. Marangoni, C. L. Burstein, and E. A. Ilovenstine, Proc. Sac. Exptl. Biol. 



Med. 44, 594 (1940). 

 " L. Perosa and A. Tarantini, Boll. soc. Hal. biol. sper. 23, 970 (1947). 

 « G. Annoni, Acta Vitaminol. 1, 65 (1947). 



" F. Muratore and T. Putignano, Boll. soc. Hal. biol. sper. 24, 270 (1948). 

 " M. Baldini and C. Cei, Boll. soc. ital. biol. sper. 22, 945 (1946). 

 " M. Baldini and C. Cei, Boll. soc. ital. biol. sper. 22, 948 (1946). 

 36 P. Merlo and G. Ercoli, Vitaminologica 1946, 104. [C. .4. 41, 5629 (1947)]. 



