Blockade by polyphloretin phosphate of the prostaglandin F2a action on isolated human bronchi.

Abstract

POLYPHLORETIN phosphate (PPP), a polymer with an inhibitory effect on some enzyme systems, such as alkaline phosphatase and hyaluronidase, has been synthesized by Diczfalusy et al.1 by phosphorylating phloretin with phosphorus oxychloride. PPP has a molecular weight of about 15,000 and is readily soluble in water at pH 7. It has been tried in the treatment of oedema2,3 and in vitro it inhibits the aggregation of red blood corpuscles4 and selectively antagonizes the effect of prostaglandin E2 (PGE2) on the intraocular pressure of the rabbit eye5. In the light of this finding we have examined whether PPP (supplied by Dr B. Hogberg) could also modify the action of prostaglandins, when tested on some other preparation— in this case isolated human bronchi. During this study an investigation of the inhibition by PPP of the PGE2 and PGF2α action on isolated bird colon, rabbit jejunum and uterus has been reported6. It has been shown that PGE1 and usually also PGE2 have a bronchodilating effect in guinea-pig7,8 and man9, while PGF2α constricts bronchial smooth muscle in vivo and invitro8,10,11. PGF2α and PGE2 have been isolated from human lungs12,13 and both seem to be released in the anaphylactic reaction of isolated guinea-pig lung.