N. Cohen et al., ATRIAL-NATRIURETIC-PEPTIDE AND PLASMA-RENIN LEVELS IN ASSESSMENT OF MINERALOCORTICOID REPLACEMENT IN ADDISONS-DISEASE, The Journal of clinical endocrinology and metabolism, 81(4), 1996, pp. 1411-1415
Assessment of mineralocorticoid replacement therapy in Addison's disea
se relies on clinical features and laboratory measurements, including
plasma renin and potassium. Previous studies have questioned the value
of measuring the plasma renin concentration (PRC), particularly in th
e setting of fludrocortisone overreplacement. The aim of this study wa
s to evaluate the usefulness of plasma atrial natriuretic peptide (ANP
) measurements as a marker of sodium and volume status in Addison's di
sease. Fourteen patients with Addison's disease receiving their usual
glucocorticoid doses were placed on various doses of fludrocortisone (
FC; 0 mg, 0.05 mg, 0.1 mg and 0.2 mg) in random order for four 2-week
periods. At the end of each period, blood pressure and clinical sympto
ms were assessed, and blood was drawn for measurement of PRC and ANP l
evels. PRC was significantly elevated in patients receiving placebo (5
4.2 +/- 57.9 ng/mL . h) compared with PRC in those receiving baseline
FC (24.7 +/- 42.4 ng/ml . h), 0.1 mg FC (15.2 +/- 25.9 ng/mL . h), and
0.2 mg FC (5.5 +/- 5.7 ng/mL . h). ANP levels were measured by either
an extraction method (ANP((ext)) or directly from plasma (ANP((dir)).
ANP((dir)) was significantly elevated at 0.2 mg FC (87.1 +/- 20.1 pg/
mL) compared with baseline (63.3 +/- 8.1 pg/mL), placebo (56.1 +/- 5.5
pg/mL), 0.05 mg FC (60.5 +/- 16.0 pg/mL), and 0.1 mg FC (65.4 +/- 13.
7 pg/mL) values. ANP((ext)) was elevated in patients receiving 0.2 mg
FC (42.7 +/- 41.8 pg/mL) compared with that in patients receiving plac
ebo (7.9 +/- 5.4 pg/mL), 0.05 mg FC (16.2 +/- 11.2 pg/mL), or 0.1 mg F
C (19.7 +/- 11.1 pg/mL). Our data suggest that PRC is of value in dete
rmining mineralocorticoid underreplacement, whereas ANP is a more sens
itive index of FC overreplacement. ANP levels may, therefore, be compl
ementary to PRC in adjustment of mineralocorticoid doses in the upper
dose range, where clinical symptoms and signs appear to be of little v
alue.