THE AMINO-TERMINAL PORTION OF PRO-BRAIN NATRIURETIC PEPTIDE (PRO-BNP)CIRCULATES IN HUMAN PLASMA

Using an antiserum raised in rabbits to a synthetic human brain natriu retic peptide (BNP) N-terminal fragment [ProBNP(1-13)], a single large molecular weight (MW) N-terminal form of ProBNP has been identified i n human plasma. Sep-pak extracts of plasma, drawn from patients with c ongestive heart failure and subjected to size exclusion and reverse ph ase high pressure liquid chromatography (HPLC) coupled to radioimmunoa ssay (RTA) revealed a single large immunoreactive (ir-) peak which was not detected in assays of BNP-32 [ProBNP(77-108)]. This material has a MW of 8600 - similar to that expected for the complete N-terminal po rtion of ProBNP(1-76). Previously reported high MW BNP forms, cross re acting with BNP-32 antisera, were not detected using the N-terminal an tisera, indicating that this material is unlikely to be intact ProBNP( 1-108). In patients with congestive heart failure plasma ir-levels of N-terminal ProBNP were greatly raised compared to normal subjects and were up to ninefold higher than ir-BNP-32 values. (C) 1995 Academic Pr ess, Inc.