Molecular forms of atrial natriuretic peptides in rat tissues and plasma.

By using the sensitive radio-immunoassay specific for rat atrial natriuretic peptide (rANP) combined with chromatographic separation, we have determined molecular forms of rANP in rat tissues and plasma. Gamma-rat atrial natriuretic peptide is a major component of rANP in rat atria and ventricles, while alpha-rANP is a predominant form in the plasma, brain and submaxillary gland. Although molecular patterns in the adrenal and thyroid glands were very similar to that in the brain, a major immunoreactive (ir) alpha-rANP peak was accompanied by two minor peaks due to gamma-rANP and another unidentified ir-rANP. This variety in molecular forms suggests that the processing system for rANP precursors differs from tissue to tissue.