Plasma concentrations of atrial natriuretic peptide in relation to body fluid status in chronic uraemia.

Basal plasma alpha-human natriuretic peptide (alpha-hANP) values were found to be significantly higher in 7 fluid-overloaded chronic dialysis patients than in 13 non-dialysed renal patients without extracellular fluid (ECF) expansion. Iso-osmotic reduction of the body weight by a single 3-h ultrafiltration caused alpha-hANP to decrease significantly in all anuric patients to values comparable to those of non-dialysed subjects. In this latter group, however, there was a significant inverse relationship between alpha-hANP and glomerular filtration rate but not between alpha-hANP and total blood volume. These findings suggest that both ECF expansion and impaired renal removal of alpha-hANP might be responsible for the high alpha-hANP in chronic uraemia.