Abstract

To elucidate the circulating forms of human atrial natriuretic peptide (hANP) in collagen disease, we analysed plasma samples obtained from 21 patients with systemic lupus erythematosus, rheumatoid arthritis or progressive systemic sclerosis with no clinical evidence of cardiac involvement. The findings were compared with those obtained from 21 healthy control subjects. Plasma hANP-like immunoreactivity was normal in all but three of the controls and in two patients with the nephrotic syndrome due to lupus nephritis. Reverse-phase high-performance liquid chromatography, gel permeation chromatography and subsequent radioimmunoassay for hANP revealed that the circulating hANP consisted of alpha-hANP, beta-hANP and gamma-hANP in the patients with collagen disease whereas alpha-hANP predominated in the control group. beta-hANP appeared in 18 of the 21 patients but was not observed in the controls. These data suggest that beta-hANP circulates in the plasma of patients with collagen disease even when no myocardial involvement is apparent and that the appearance of beta-hANP is not always associated with an increase in total plasma hANP-like immunoreactivity. Thus the appearance of beta-hANP in plasma is not a phenomenon specific to congestive heart failure.