Atrial natriuretic peptide and 24 hour blood pressure

Background. Atrial natriuretic peptide (ANP) is a hormone involved in the cardiovascular modulation of blood pressure and volume homeostasis. Objective. To compare ANP levels in normotensives and hypertensives and to correlate ANP levels with ambulatory blood pressure parameters. Methods. Plasma samples for ANP determination (using a double-antibody radioimmunoassay Kit) were obtained from 33 consecutive subjects (24 hypertensives, nine normotensives) who had rested supine for 30 min. Afterwards, all of the subjects were subjected to 24 h non-invasive blood pressure monitoring. We found no significant difference between the two groups with regard to ANP levels (95.1 ± 29 versus 96.9 ± 33 pg/ml, in normotensives and hypertensives, respectively). Also, when hypertensive patients were divided according to their family history of hypertension, ANP levels were similar. There was no correlation between the ANP level and the pre-sampling blood pressure or between the ANP level and the following ambulatory blood pressure monitoring parameters: 24 h, diurnal and nocturnal systolic and diastolic blood pressures, systolic and diastolic loads, nocturnal blood pressure reduction and blood pressure variation coefficients. Conclusion. Both the pre-sampling blood pressure and ambulatory monitoring results (sustained blood pressures and pressure variations during the 24 h period) do not seem to influence basal ANP levels in patients with hypertension, These data do not account for a role of this peptide in cardiovascular control, in hypertension.