title: Identification of amino-terminal pro-C-type natriuretic peptide in human plasma.
abstract: We report the first identification of a circulating peptide from the amino-terminal end of proCNP. A specific radioimmunoassay was established based on antisera to the synthetic peptide proCNP(1-15). Extracts of plasma, drawn from patients with congestive heart failure or from sheep with experimental heart failure, were subjected to size exclusion and reverse-phase high-pressure liquid chromatography (HPLC) coupled to radioimmunoassay (RIA). These studies revealed the presence of an immunoreactive peptide with a molecular weight (M(r) approximately 5 kDa) similar to that expected for NT-proCNP(1-50), a potential fragment released during processing of pro(CNP). The same material was isolated from extracts of homogenized ovine pituitary, a tissue known to be a relatively enriched source of CNP. Plasma NT-proCNP levels in 22 patients with congestive heart failure (9.7 +/- 0.5 pmol/L, mean +/- SEM, range 5.4-13.7 pmol/L) were raised (P = 0.003) compared to those in 16 healthy volunteers (7.4 +/- 0.3 pmol/L, range 5.7-10.7 pmol/L) and were higher than levels reported for CNP in similar subjects. This first identification of circulating NT-proCNP opens the possibility of studying the factors regulating CNP production and metabolism in vivo.
authors.affiliation: Department of Medicine, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand. tim.prickett@chmeds.ac.nz
authors.forename: T C
authors.initials: TC
authors.lastname: Prickett
authors.forename: T G
authors.initials: TG
authors.lastname: Yandle
authors.forename: M G
authors.initials: MG
authors.lastname: Nicholls
authors.forename: E A
authors.initials: EA
authors.lastname: Espiner
authors.forename: A M
authors.initials: AM
authors.lastname: Richards
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006333:Heart Failure / Q000097:blood; D006801:Humans; D008297:Male; D008956:Models, Chemical; D020098:Natriuretic Peptide, C-Type / Q000097:blood* / Q000737:chemistry* / Q000276:immunology; D010455:Peptides / Q000032:analysis; D011498:Protein Precursors / Q000097:blood / Q000737:chemistry / Q000276:immunology; D011863:Radioimmunoassay / Q000379:methods; D012756:Sheep; D014020:Tissue Extracts / Q000737:chemistry
chemical_list: D010455:Peptides; D011498:Protein Precursors; D014020:Tissue Extracts; D020098:Natriuretic Peptide, C-Type