Atrial natriuretic peptide during mineralocorticoid escape in the human

The relationship between plasma atrial natriuretic peptide (ANP) and mineralocorticoid escape was examined in six normal men (age, 20−32 yr) treated with 0.4 mg/day fludrocortisone acetate for 9−14 days. Urinary sodium excretion decreased from 162 ± 15 (sem) meq/24 h before to 97 ± 10 meq/24 h during fludrocortisone acetate administration (P < 0.05). Despite continued fludrocortisone acetate administration, sodium excretion subsequently returned to baseline (escape). Plasma ANP increased from 33 ± 6 pg/ml (control) to 55 ± 14 pg/ml on the first day of escape (P < 0.05). Escape was associated with a decrease in PRA from 0.90 ± 0.22 (control) to 0.26 ± 0.08 ng/ml·h (escape, P < 0.05). The escape phenomenon was not associated with a significant change in mean arterial pressure or glomerular filtration rate. This study demonstrates that mineralocorticoid escape is temporally related to a significant increase in circulating ANP.