Plasma saluretic activity: its nature and relation to oxytocin analogs.

Plasma natriuretic activity was evoked in cows and dogs by infusion of saline with or without dextran. Deproteinized samples were fractionated on both Sephadex and Bio-Gel columns; the activity was separated, the approximate molecular weight being in the region of 1000. Incubation with chymotrypsin destroyed the activity, suggesting that it might be a polypeptide. A similar activity in blood resulted from intracarotid injection of either oxytocin or either of two synthetic analogs. Possibly the latter are saluretic by virtue of a releasing action on some intracranial structure for another natriuretic peptide.