The presence and molecular forms of cardiodilatin immunoreactivity in the human and rat right atrium.
A sensitive and specific radioimmunoassay has been developed for cardiodilatin, the N-terminal peptide sequence of the atrial natriuretic peptide (ANP) prohormone. Cardiodilatin-immunoreactivity (-IR) concentrations in the human right atrial appendage were found to correlate with ANP-IR concentrations, determined by an established radioimmunoassay, (cardiodilatin-IR = 13.2 +/- 1.2 nmol/g, ANP-IR = 19.8 +/- 2.0 nmol/g, r = 0.80, p less than 0.001). Characterisation of the cardiodilatin-IR in the human and rat right atrium by gel permeation and fast protein liquid chromatography revealed only two cardiodilatin-IR molecular forms. The larger more hydrophobic form, the majority of the cardiodilatin-IR, contained in addition ANP-IR and therefore represents the prohormone. The smaller, less hydrophobic form, lacked ANP-IR and thus represents the cleaved N-terminal peptide sequence of the prohormone. These findings indicate that the prohormone is the major molecular form in the human and rat atrium. Furthermore, they demonstrate that a single large N-terminal peptide, cardiodilatin, derived from the prohormone, may exist as a distinct molecular form in the atrium of these species.
Meleagros
L
L
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Ghatei
M A
MA
Anderson
J V
JV
Wharton
J
J
Taylor
K M
KM
Krikler
D M
DM
Meijler
F L
FL
Polak
J M
JM
Bloom
S R
SR
D000818:Animals; D009320:Atrial Natriuretic Factor; D001483:Base Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006325:Heart Atria / Q000032:analysis*; D006352:Heart Ventricles / Q000032:analysis; D006801:Humans; D009124:Muscle Proteins / Q000032:analysis* / Q000276:immunology; D011487:Protein Conformation; D011863:Radioimmunoassay; D051381:Rats
D009124:Muscle Proteins; D009320:Atrial Natriuretic Factor; C040651:cardiodilatin