A vasopressor lipid in incubated plasma

Abstract

The presence of a new factor, vasopressor in rats and oxytocic on rats' uteri, has been demonstrated in plasma of dogs, cats, pigs and human beings incubated at 37°C for 24 hours. It is different from the adrenergic amines and the pressor polypeptides and is probably a lysophosphatide produced by an enzymatic reaction in plasma. This enzyme has a broad pH optimum of 8–9, and requires both calcium and phosphate ions for activity. The phosphate ions can be replaced by arsenate, and the enzyme is inhibited by ethylenediaminetetraacetic acid and pyrophosphate. Similar vasopressor and oxytocic effects can be produced by the action of rattlesnake venom on lecithin (animal, impure) dissolved in ether. The plasma factor and the snake venom factor cannot be separated by countercurrent distribution or silicic acid chromatography.