Source of ‘Serotonin’ in Serum

Abstract

RAPPORT et al.¹ prepared from beef serum a vasoconstrictor substance which was called ‘serotonin’. By following the pharmacological activity through various stages from serum itself to the final product, it was considered that the substance finally isolated is, in fact, that responsible for the well-known vasoconstrictor activity of serum. The latter substance, which elsewhere² has been called ‘thrombocytin’, depends on the presence of platelets in plasma at the time of clotting^3,4. For this reason we have repeated Rapport's procedure, applying it to serum prepared from highly centrifuged plasma, on one hand, and to serum prepared from platelet-rich plasma, on the other.