Isolation of myocardial depressant factor from plasma of dogs in hemorrhagic shock.

Starting with 31 of plasma from dogs in hemorrhagic shock, we have purified the myocardial depressant factor and found that the activity is separate from salts and free amino acids. Moreover, the myocardial depressant factor is present in shock plasma in concentrations of about 1 nmol/ml of plasma. The depressant factor exists as multiple chromatographic forms. The best characterized forms are the anionic forms. A preliminary amino acid composition of the anionic forms has been obtained. These findings should allow more rapid processing of plasma containing high myocardial depressant factor activity to separate the factor and to completely identify this small peptide of great physiologic interest.