Antagonism to the diuretic action of SR 720-22.

SummaryEx 4877 blocked the diuretic effects of SR 720-22, a quinazolinone, indicating a broader spectrum of blocking action for Ex 4877 and a similarity in the mode of action between hydrochlorothiazide and SR 720-22. The results support the findings by Small and Cafruny (2) that Ex 4877 does not block the diuretic effects of furosemide.The authors wish to thank Mr. Frederick Kaiser and Mrs. Bette Van Denburg for technical assistance and Mr. Madhusudan Trivedi for statistical analysis of the data. Ex 4877 was kindly supplied by Dr. John Suh, Lakeside Laboratories, Inc., Milwaukee, Wisconsin.