Platelet activating factor in surfactant-TA is inhibited by coexisting inhibitors.
To clarify whether or not the platelet activating factor (PAF) present in surfactant-TA (calf-lung extract) is harmful, we investigated the activity and inhibitory activity of PAF in a surfactant preparation using a bioassay with washed rabbit platelets. The surfactant-TA contained PAF at 11-21 pmol/vial. The fractions of lysophosphatidylcholine, sphingomyelin, phosphatidylserine plus phosphatidylinositol, and phosphatidylglycerol dose-dependently inhibited the aggregation of washed rabbit platelets induced by PAF. Surfactant-TA contained sufficient amounts of these phospholipids to inhibit the PAF activity completely. These results suggest that coexisting PAF inhibitors protect the lung from the harmful effects of PAF in surfactant-TA.
Koyama
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Department of Pediatrics, Saitama Medical Center, Saitama Medical School, 1981 Kamoda-Tsujido, Kawagoe, Saitama 350-8550, Japan. n.koyama@nifty.com
D000818:Animals; D001681:Biological Assay; D001688:Biological Products / Q000737:chemistry; D002417:Cattle; D010743:Phospholipids / Q000494:pharmacology*; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors*; D011817:Rabbits
D001688:Biological Products; D010743:Phospholipids; D010972:Platelet Activating Factor; C072197:beractant