Tohru Yamaji

Atrial Natriuretic Factor in Human Blood

To determine whether atrial natriuretic factor (ANF) is a circulating hormone in men, a radioimmunoassay suitable for the estimation of ANF in human plasma was developed and the nature of plasma ANF was characterized. Plasma ANF was extracted before radioimmunoassay by affinity chromatography on a column of ANF antibody-coupled agarose. When plasma ANF extract was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with the radioimmunoassay of the eluted gel slices for ANF, almost all of the ANF activities ran in the 3,000-mol-wt area, while three peaks of ANF were observed in human atrial tissue extract, molecular weights of which corresponded to 14,000, 6,000, and 3,000, respectively. Reversed-phase high performance liquid chromatography of atrial tissue extract resolved multiple forms of ANF. In contrast, one major peak was observed in human plasma extract, and its retention time coincided with that of synthetic human alpha-atrial natriuretic polypeptide. When 500 ml of 0.9% saline was infused into six healthy subjects over 45 min, plasma levels of ANF were unequivocally elevated. The mean plasma ANF concentrations rose from the baseline (23.0 +/- 2.5 pg/ml, mean +/- SEM, n = 6) to the peak (41.8 +/- 4.9 pg/ml, mean +/- SEM) at 75 min postinfusion. No significant change in plasma ANF, on the other hand, was found in the control group. These results suggest that ANF is a circulating hormone in men and is secreted in response to isotonic volume expansion.

Clinical Evaluation of the Plasma Levels of Immunoreactive Atrial Natriuretic Peptide in Elderly Patients with Heart Diseases

Plasma levels of immunoreactive atrial natriuretic peptide (ANP) were estimated in 69 elderly patients over 60 years of age (mean 76.4 years) with or without heart diseases and in ten young, healthy volunteers (mean 33.0 years) to evaluate the clinical significance of ANP in the elderly. Plasma ANP levels in nine patients without heart diseases were significantly (P < .01) higher than in the ten young, healthy subjects (mean ± SD, 46.0 ± 22.0 vs 22.1 ± 6.3 pg/mL) and a significant positive correlation was observed between ANP level and age in these subjects (r = 0.60, P < 0.01). Plasma ANP levels in 60 patients with heart diseases (158.4 ± 158.5 pg/mL) were significantly (P < 0.05) greater than in nine patients without heart diseases. Plasma ANP levels in patients with congestive heart failure or atrial fibrillation were 285.8 ± 185.2 or 223.0 ± 185.9 pg/mL, respectively; each of these values was significantly (P < 0.01) higher than in patients without heart diseases. In three patients with paroxysmal atrial fibrillation, plasma ANP levels during atrial fibrillation were three times greater than when atrial fibrillation returned to normal sinus rhythm (377.3 ± 78.5 vs 101.1 ± 68.5 pg/mL).

Atrial natriuretic peptide with artificial pacemakers

Abstract Accumulating evidence indicates that atrial natriuretic peptide (ANP) is a circulating hormone in humans. 1–4 Plasma levels of ANP increase in patients with various heart diseases such as paroxysmal atrial arrhythmias 2 and congestive heart failure. 3,4 If atrial stretching due to increased atrial pressure stimulates ANP secretion, 4 plasma ANP levels may be altered in patients with bradyarrhythmias and in those with pacemaker syndrome, a major clinical complication in patients in whom artificial pacemakers are implanted. 5 To clarify the role of ANP in the pathophysiology of these states, we examined plasma ANP levels in patients with bradyarrhythmias and in those treated with pacemakers of various modes.