title: Effects of changes in intravascular volume on atrial size and plasma levels of immunoreactive atrial natriuretic peptide in uremic man.
abstract: To study the trigger for the release of atrial natriuretic peptide (ANP) in man, we measured the atrial areas (AA) by 2-D echocardiography, the total blood volume (TBV) by 131I-serum albumin and plasma immunoreactive ANP (i-ANP) concentrations by radioimmunoassay, after prior plasma extraction, for 10 dialyzed uremic patients. Measurements were made when the patients were volume-loaded or volume-depleted by isoosmotic ultrafiltration and again 48 h later, when they were again volume-loaded. Analysis of plasma extracts by high-performance gel permeation chromatography revealed that the greatest amount of the i-ANP fraction was a peptide eluting like human synthetic alpha-ANP. Ultrafiltration consistently decreased the TBV, while spontaneous regain of body-fluids caused TBV to rise to pre-ultrafiltration levels. Changes in TBV were closely related in time to changes in both right (RAA) and left (LAA) atrial area and in plasma i-ANP concentrations. Significant direct relationships were found between TBV and RAA, TBV and i-ANP and between both LAA and RAA and i-ANP. Furthermore, the decreases and the increases in TBV, RAA and LAA were closely correlated with changes in i-ANP. Multiple regression analysis, however, revealed that the changes in plasma i-ANP were mainly related to the changes in RAA, with little or no relationship to the changes in TBV or LAA. These findings are evidence for a positive feed-back between the level of intravascular filing volume, extent of atrial distention and amount of i-ANP released into the blood stream.
authors.affiliation: Division and Chair of Nephrology, Institute of Chemistry, School of Medicine, Brescia, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cannella
authors.forename: A
authors.initials: A
authors.lastname: Albertini
authors.forename: D
authors.initials: D
authors.lastname: Assanelli
authors.forename: S
authors.initials: S
authors.lastname: Ghielmi
authors.forename: C
authors.initials: C
authors.lastname: Poiesi
authors.forename: M
authors.initials: M
authors.lastname: Gaggiotti
authors.forename: M
authors.initials: M
authors.lastname: Sandrini
authors.forename: O
authors.initials: O
authors.lastname: Visioli
authors.forename: R
authors.initials: R
authors.lastname: Maiorca
mesh_terms: D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood* / Q000276:immunology; D001810:Blood Volume; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D014511:Uremia / Q000097:blood* / Q000503:physiopathology / Q000628:therapy
chemical_list: D009320:Atrial Natriuretic Factor