Diuresis from stimulation of left atrial receptors: initial purification steps from plasma of the causative agent

This paper reports the initial purification steps of a humoral agent which may mediate the diuresis resulting from stimulation of left atrial receptors in anaesthetized dogs. The agent was shown to be stabilized in plasma by acidification to pH 3.2. Acid acetone precipitation was found to be a convenient method as a first stage in the purification of the humoral agent in plasma. Heat stability studies showed that the agent was stable in acidified plasma for up to 20 min of heating in a boiling water bath. Precipitation of plasma proteins under these conditions made this another possible first stage in the purification of the agent in plasma. Some general conclusions about the possible nature of the humoral agent are discussed.