Pressor Substances in Arterial Hypertension

Some pharmacological and chemical qualities of pherentasin, a vasoconstrictor substance procured from human hypertensive blood, were studied by a new assay method using the spirally cut rabbit aorta. Of a number of drugs tested, six metal-binding agents including hydralazine inactivated the active principle. The material was stable in acid but not in alkali. It was destroyed by drying. Chemical analysis and inactivation procedures suggested the presence of primary amine and considerable sulfur; a peptide linkage was suspected because of inactivation by manganous ion and papain. The material was remarkably resistant to most pharmacological agents and appeared to act directly on smooth muscle.