A MICROMETHOD FOR DETERMINATION OF BRADYKININOGEN UNDER SEVERAL CONDITIONS *

The study of the bradykinin precursor-bradykininogen(BKG)in plasma or other biological fluids is of obvious importance in understanding the role of this polypeptide in several physiological and pathological conditions. The determination of the BKG variations under various circumstances might give an insight in the extent of the mobilization of the biochemical process responsible for the release of bradykinin in blood. Bradykinin itself is difficult to assay in blood because i t is on one hand quickly destroyed by the powerful bradykininolytic enzymes present in this fluid and on the other hand i t is diluted in the extracellular fluids of the animal body. From a biochemical point of view it is also of interest to understand the metabolic alterations of such a specific protein as BKG under a variety of experimental and clinical conditions. As a first step, a simplified method for BKG determination was developed in this laboratory.' The method and its use in the study of some experimental and clinical problems will be reviewed in this paper.