Variable patterns of atrial natriuretic peptide secretion in man

Abstract

Peripheral circulating levels of atrial natriuretic peptide may exhibit short-term variation compatible with a pulsatile pattern of secretion. We obtained samples every 2 min for 90 min from the antecubital vein of 16 patients with chronic cardiac failure and 13 controls. Overall levels were higher in the patients (median and quartiles 230 (125,325) vs. 26 (16,48) ng l-1; P < 0.001). In both groups there was considerable variability, with 10 (2-12) peaks, 9 (7-15) troughs (both defined as > 2 SD from the mean) and 16 (13-18) pulses (defined by computer) during the sampling period in controls, and a similar number in patients. We then carried out simultaneous sampling in the pulmonary artery, femoral artery and peripheral vein in eight subjects with normal cardiac function and six patients with impaired function due to valvular heart disease. The pattern of variability was preserved in all three sites in both groups, suggesting intermittent secretion rather than variable breakdown of the peptide in the lung. No changes in right atrial pressure or heart rate were observed to coincide with the variations, but levels of the peptide in the pulmonary artery correlated with right atrial pressure in patients (r = 0.87; P < 0.05). The mechanism of such periodicity and its pathophysiological importance remain unknown.

Prognostic Value of Plasma N-Terminal Pro-Brain Natriuretic Peptide in Patients With Severe Sepsis

“…Whereas plasma concentrations of the C-terminal peptides BNP and ANP are low and fluctuate rapidly, 26 half-life times of the N-terminal peptides NT-proANP and NT-proBNP are considerably longer, 27,28 resulting in at least 5-to 15-timesgreater plasma levels. The N-terminal peptides may therefore be even more sensitive for the detection of left ventricular dysfunction in critical care settings because they are less influenced by the conditions under which the blood sample is taken.…”

The natriuretic peptide family

“…During exercise in such patients the relative increase in ANP levels is less than in normal subjects [35]. This is probably not due to a ceiling on ANP release, as intermittent very high levels may still be recorded [24]. It has been suggested that the major circulating form in patients is the antiparallel dimer of alpha ANP, termed P-ANP, which has reduced biological activity [36], but recent work in our laboratories suggest that this may not be the case.…”

“…Recent studies have suggested that there may be short-term variations in the release of ANP independent of heart rate or right atrial pressure, which can give rise to peak levels about every 10-12min [23,24]. The significance of these observations is, at present, unclear, but it does mean that isolated values should be interpreted with caution.…”

Distribution of Calcitonin Gene-Related Peptide, Atrial Natriuretic Peptide and Neuropeptide Y in the Rat Heart

“…Radioimmunoassay and Immunocytochemical Studies of Peptides in the Rat Heart Cardiology 1998;90:95-100 97 er related analogues was also used [18]. The primary antisera were applied at their optimal working dilution and incubated for 20 h at 4°C in a sealed moist container.…”

“…The extracts were centrifuged at 1,700 g for 30 min at 4°C, the supernatants decanted, air-dried and stored at -20°C prior to radioimmunoassay. Radioimmunoassay of hANP and NPY were performed using antibody to ·-hANP, and C-terminal NPY hexapeptide analogue and methology established [18][19][20][21]. The sensitivity of the assays were 1.2 fmol ANP/assay tube and 20 ng/l for NPY.…”