atrial-natriuretic-factor and Acromegaly

Topics: Absorptiometry, Photon; Acromegaly; Animals; Atrial Natriuretic Factor; Body Fluids; Body Water; Extracellular Space; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Kidney; Male; Plasma Volume; Renin-Angiotensin System; Tomography, X-Ray Computed; Water-Electrolyte Balance

Atrial natriuretic peptide is a recently discovered cardiac hormone with natriuretic, vasodilatory and hypotensive activities. The role of this hormone in the pathophysiology of hypertension is of particular interest. In contrast to an earlier concept, a deficiency of the atrial peptide could not be found in animal models of hypertension or in patients. ANP plasma levels were elevated in SHR with accelerated hypertension, in salt-sensitive Dahl rats, in rats with DOCA-salt-hypertension and in animals with renovascular hypertension. Elevated ANP levels under these conditions can be explained by an expansion of the intravascular volume or by an elevated atrial wall stretch induced by the hypertension itself. In patients with primary hypertension, plasma levels of the peptide are raised in some patients and are normal in others. Plasma ANP levels correlate with age, blood pressure and signs of left ventricular hypertrophy. A negative correlation is described between ANP and renin. Measurement of plasma ANP levels does not allow a differentiation between primary and secondary forms of hypertension. Elevated ANP levels are also found in primary hyperaldosteronism and in renal failure. Stimulation of ANP secretion by physical exercise and dietary salt loading is maintained in hypertension. Infusion of 1-28-hANP leads to a reduction in systemic arterial pressure in normotensives and hypertensives. The natriuresis induced by exogenous ANP is more pronounced in hypertensives. Stimulation of endogenous ANP secretion does not prevent the rise in blood pressure possibly due to a reduction in ANP receptors in target tissues.

Topics: Acromegaly; Animals; Atrial Natriuretic Factor; Humans; Hyperaldosteronism; Hypertension; Hypertension, Renal; Hypertension, Renovascular; Kidney Failure, Chronic; Male; Rats; Rats, Inbred Strains

The radioimmunologic assays appeared to be the most convenient methods for determination of atrial natriuretic peptide (ANP) concentration in blood plasma. The purpose of this work was to compare the control quality parameters of two radioimmunologic methods for the ANP determination in human plasma: the methods described by Pruszczyński et al. and the method with the use of Amersham ready-made set (kit). The comparison of the two methods was performed by analyzing 10 series of ANP determinations carried out by Pruszczyński method, and 15 series by means of the kit. Both methods appeared to fulfil the criteria of satisfactory quality for RIA determinations. The second purpose of this study was to define the utility of the RIA method for the determination of ANP in clinical practice, taking into the consideration some factors influencing or modifying plasma ANP levels. Three groups of persons of were studied: 15 healthy subjects, 16 patients with acromegaly and 47 patients with the impairment of renal function. The ANP level in plasma was determined in these 3 groups of persons. It has been demonstrated that the change of body position from upright to supine caused the increase of the ANP concentration in plasma. It has also been found that the decrease in the intravascular fluid volume induced by furosemide administration resulted in the reduction of ANP concentration in plasma. The enlarged intravascular fluid volume, accompanying acromegaly and probably present in persons with the impairment of kidneys, was associated with the increased ANP concentrations in plasma.

Topics: Acromegaly; Adult; Atrial Natriuretic Factor; Blood Pressure; Diagnostic Errors; Female; Furosemide; Humans; Injections, Intravenous; Kidney Failure, Chronic; Male; Middle Aged; Poland; Posture; Quality Control; Radioimmunoassay; Reagent Kits, Diagnostic

Atrial natriuretic hormone is involved in the control of blood pressure and water-electrolyte balance. In order to assess the relationship between atrial natriuretic hormone and hypertension in acromegaly, 34 subjects were studied, 18 with acromegaly (10 normotensive and 8 hypertensive) and 16 healthy controls. Plasma atrial natriuretic hormone levels, as well as plasma renin activity, aldosterone and growth hormone levels were measured in basal conditions in all subjects. Additionally, plasma renin activity and aldosterone levels were determined after standard stimulation. In hypertensive acromegalic patients, atrial natriuretic hormone plasma concentrations (39.8 +/- 3.5 ng/l) were significantly higher than in patients without hypertension (27.9 +/- 4.1 ng/l), and in controls (28.6 +/- 1.3 ng/l) (p less than 0.01 in both comparisons). Stimulated plasma renin activity values were decreased in hypertensive acromegalic patients when compared with those in normotensive patients (1.14 +/- 0.29 vs 4.03 +/- 0.66 micrograms.l-1.h-1, p less than 0.01). In acromegaly, atrial natriuretic hormone levels correlated with mean arterial pressure (r = 0.58, p = 0.01). These results suggest that atrial natriuretic hormone plasma levels are slightly increased in patients with acromegaly and hypertension.

Topics: Acromegaly; Adult; Aldosterone; Analysis of Variance; Atrial Natriuretic Factor; Blood Pressure; Female; Humans; Hypertension; Male; Middle Aged; Potassium; Renin; Sodium

In acromegaly the plasma volume is chronically elevated and it returns to normal when the disease is successfully treated. To define the role of ANF in such a chronic disorder of extracellular fluid volume homeostasis the plasma level was assayed in 37 acromegalic patients with active or inactive (successfully treated) disease. Five patients were studied before and after therapy. The effects of acute change in sodium-fluid status on plasma ANF levels was examined in 7 active and 4 inactive acromegalic patients and in 7 healthy subjects. As compared to 14 patients with inactive acromegaly, 23 patients with active acromegaly had an expanded plasma volume (n = 12; 50.1 vs 37.6 ml.kg-1 BW) and an increased blood concentration of growth hormone (n = 23; 22.5 vs 2.1 ng.ml-1). Plasma ANF concentrations in active and inactive acromegalic patients (33.2 and 26.6 pg.ml-1, respectively) did not differ significantly from one another or from the level in the controls (26.9 pg.ml-1). In those patients there was no correlation between plasma volume and ANF level. Infusion of 21 isotonic saline in 2 h led to a similar, significant increase in ANF levels in active (from 26.2 to 72.4 pg.ml-1) and in inactive acromegalic patients (from 33.6 to 96.7 pg.ml-1) as well as in healthy subjects (from 21 to 70.6 pg.ml-1). Successful treatment reduced the plasma volume (from 49.2 to 35.8 ml.kg-1 BW) and growth hormone level (from 10.1 to 2.6 pg.ml-1), while the ANF level remained unchanged (from 33.8 to 35.5 pg.ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acromegaly; Adult; Atrial Natriuretic Factor; Female; Heart Failure; Hormones; Humans; Iodine Radioisotopes; Male; Middle Aged; Plasma Volume; Radioimmunoassay

We have studied plasma ANF before and after a 4-h intravenous infusion of normal saline in eight subjects with active acromegaly and in eight age and sex-matched control subjects. Plasma ANF, serum aldosterone and blood pressure were measured basally and after 2 and 4 h and plasma renin activity basally and after 4 h. Basal plasma ANF was similar in each group (4.4 +/- 1.5 pmol/l (mean +/- SEM) in acromegalic subjects and 5.3 +/- 0.7 pmol/l in controls NS). Plasma ANF did not rise significantly after saline in the acromegalic group (2-h value, 5.9 +/- 0.9; 4-h value, 5.1 +/- 0.9 pmol/l) but did rise significantly in the control group (2-h value, 8.9 +/- 1.9; 4-h value 9.5 +/- 1.3 pmol/l, both values P less than 0.05 vs basal level). The 4-h ANF value was significantly higher in the control group than in the acromegalic group (P less than 0.05). Basal and stimulated serum aldosterone values were similar in the two groups. Plasma renin activity suppressed to a lesser extent in the acromegalic group after 4 h. The facts that basal plasma ANF was not raised in acromegalic subjects and did not respond to saline stimulation demonstrate that an abnormality of ANF control may be an important factor in the aetiology of the expanded sodium status of patients with acromegaly and hence may contribute to the hypertension seen in patients with growth hormone excess.

Topics: Acromegaly; Adult; Aldosterone; Atrial Natriuretic Factor; Blood Pressure; Female; Humans; Male; Middle Aged; Renin; Sodium Chloride; Urea

Topics: Acromegaly; Adult; Aldosterone; Atrial Natriuretic Factor; Female; Growth Hormone; Humans; Male; Middle Aged; Plasma Volume; Posture; Renin

Atrial natriuretic peptide (ANP) is a hormone release into the circulation by atrial cardiocytes (Gutkowska et al. 1984). Extracellular fluid volume expansion acts as a powerful stimulus for ANP secretion and results in the augmentation of its plasma concentration (Lang et al. 1985). Patients with active acromegaly demonstrate the increased extracellular fluid volume (Falkheden et al. 1964), while a successful treatment of the disease results in the disappearance of hypervolemia (Strauch et al. 1977). We have recently demonstrated that in patients with active acromegaly the increased total body plasma volumes are accompanied by the elevated plasma ANP concentrations, whereas, in the successfully treated patients, both: total plasma volumes and plasma ANP levels do not differ significantly from these in healthy subjects (Czekalski et al. 1988b).

Topics: Acromegaly; Atrial Natriuretic Factor; Extracellular Space; Female; Furosemide; Humans; Male; Water-Electrolyte Balance

Topics: Acromegaly; Adult; Atrial Natriuretic Factor; Female; Glucagon; Humans; Insulin; Male; Middle Aged