AJP - Endocrinology and Metabolism, Vol 261, Issue 4 E525-E528, Copyright © 1991 by American Physiological Society
Big ANF: large-molecular-weight ANF in rabbit plasma. II. Acid dissociation and HPLC of dissociated irANF
N. Wilson, V. Yakoleff and J. R. Claybaugh
Department of Physiology, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
A large-molecular-weight form of atrial natriuretic factor (ANF) was found
in rabbit plasma. When extraction of plasma utilizing octadecylsilane
cartridges is employed, this big ANF is not retained by the cartridge. When
this material is dissociated with acid, immunoreactive ANF (irANF) is
released. Of the acids tested, formic and acetic acid (0.05 M) were
indicated as the most effective in causing the dissociation.
High-performance liquid chromatography analysis of dissociated ANF,
confirmed by coelution with synthetic peptides, disclosed the presence of
ANF-(99-126) and ANF-(103-126) in a ratio of approximately 2:1. Atriopeptin
I was detected in most of the samples analyzed, but atriopeptin II was only
detected in one analysis. Despite the wide spectrum of the antiserum used
for detection of irANF in the eluent fractions, only immunoreactive peaks
coeluting with the four standards were detected. We therefore conclude that
big ANF is a bound form of atrial peptides found in normal circulation.
