58 P-AMINOBENZOIC ACID 



b. Miscellaneous 



In studies utilizing the Warburg technique and bioassay in ovariec- 

 tomized rats, Ansbacher et al.^^ found that PABA inhibited the destruction 

 of stilbesterol. Possibly a similar effect was noted recently by Wiesel et al.^^ 

 in that PABA made possible a marked reduction in the cortisone require- 

 ments of rheumatoid arthritic patients. 



8. Detoxicating Action 



In a series of papers, Sandground and Hamilton*^^-"^ reported that PABA 

 was highly effective in affording protection against high lethal doses of 

 certain pentavalent arsenicals and antimonials. This protective action of 

 PABA did not interfere with the trypanocidal activity of the metalloids. 

 If injected before the arsenical, PABA protection was maximal. The effect 

 was distinctly reduced when PABA was administered after the toxic agent, 

 and protection was further decreased with increasing time interval. This 

 would suggest a competitive effect for action on some receptor, but no 

 chemical similarity was noted. Protection was not afforded against the 

 trivalent arsenicals, inorganic arsenious acid, mapharsen and arsphenamine, 

 or tartar emetic (trivalent antimonial). However, PABA did protect 

 against neoarsphenamine, and this was confirmed by McChesney et al.^'' 

 Peters^^ also found no detoxicant action by PABA against mapharsen. The 

 mechanism of protection was studied by Harris, ^^ who showed a decrease 

 in extent and severity of renal damage of rats treated with PABA as com- 

 pared with animals which received only the toxic drug. 



Inhibition of the convulsive action of procaine by PABA was reported 

 by Richards and Kueter.'^"' '^^ However, the peripheral local anesthetic 

 effect of procaine was not inhibited. The chemical similarity here is obvious. 



Voss and Tatum" found a definite, although low-grade, protection by 

 PABA against certain organic bismuth preparations in rats. 



«o S. Ansbacher, W. A. Wisansky, and G. J. Martin, Federation Proc. 1, 98 (1942). 



61 L. L. Wiesel, A. S. Barritt, and W. M. Stumpe, Am. J. Med. Sci. 222, 243 (1951). 



62 J. H. Sandground, Science 97, 73 (1943). 



63 J. H. Sandground, Proc. Soc. Exptl. Biol. Med. 52, 188 (1943). 



64 J. H. Sandground and C. R. Hamilton, J. Pharmacol Exptl. Thcrap. 78, 109, 203 

 (1943). 



65 J. H. Sandground, J. Pharmacol. Exptl. Therap. 78, 209 (1943). 



66 J. H. Sandground and C. R. Hamilton, /. Lab. Clin. Med. 28, 1821 (1943). 



67 E. W. McChesney, O. W. Barlow, and O. TI. Klinck, Jr., J. Phnrmncol. Exptl. 

 Therap. 80, 81 (1944). 



68 L. Peters, Proc. Soc. Exptl. Biol. Med. 53, 147 (1943). 



69 P. N. Harris, J. Pharmacol Exptl. Therap. 82, 254 (1944). 

 '0 R. K. Richards, J. Biol. Chem. 159, 241 (1945). 



" R. K. Richards and K. E. Kuoter, J. Pharmacol. Exptl. Therap. 87, 42 (.1946). 

 " E. Voss and A. L. Tatum, J. Pharmacol. Exptl. Therap. 90, 161 (1947). 



