Atrial Natriuretic Hormone Release Research Articles

Atrial natriuretic hormone in lactate-induced panic attacks: mode of release and endocrine and pathophysiological consequences

Previous studies have shown unequivocally a lack of pituitary-adrenocortical stress hormone activation during lactate-induced panic attacks despite considerable psychopathological alterations, signs of arousal and several vegetative symptoms regularly occurring during stressful conditions. To study the possible inhibitory action of atrial natriuretic hormone (ANH) on adrenocorticotrophic hormone (ACTH) and cortisol release in humans, 10 patients with panic disorder (DSM-III-R) received sodium lactate and placebo (0.9% saline) infusions and ten healthy comparison subjects additionally received a 2.5% saline infusion and the response of ANH, vasopressin, ACTH, cortisol, and several biochemical and physiological cardiovascular parameters were measured. In comparison to placebo, lactate infusion led to enhanced ANH levels in both non-panicking comparison subjects and panickers. Importantly, panickers showed significantly lower baseline levels of ANH than comparison subjects followed by a faster release. No significant concomitant changes in vasopressin, ACTH, and cortisol were observed. During lactate infusion, heart rate was accelerated considerably in the two groups; in contrast, the reduction of pCO 2 indicated an enhanced ventilation only in panickers. The pattern of ANH release cannot be attributed simply to either the volume load administered, the cardiac activation or an osmotic effect since neither 0.9 nor 2.5% saline resulted in comparable effects. Additional central nervous mechanisms must be considered for the increased ANH concentrations in lactate-induced panic attacks. We propose that the release of ANH is an intrinsic mechanism contributing to the apparent unresponsiveness of the pituitary-adrenocortical system in lactate-induced panic attacks. In addition, we surmise that ANH may also play a role in the yet unknown mechanisms for termination of panic attacks e.g. either by inhibitory actions on the locus coeruleus or by bronchiorelaxation and consecutive decatastrophization.

Plasma atrial natriuretic hormone in hyperthyroidism

In 22 hyperthyroid patients, atrial natriuretic hormone (ANH) levels (71.91 ± 21.03 pg/ml), measured during a 3-h-Holter, were found to be significantly higher (p<0.001) than those in 20 age-matched normal subjects (37.22 ± 8.73 pg/ml). We have demonstrated that the presence of tachiarrhythmias does not influence ANH release.The positive and significant correlation of FT3 with both ANH and heart rate confirms the hypothesis of a direct action of thyroid hormones on ANH release.

Impaired vasopressin suppression and enhanced atrial natriuretic hormone release following an acute water load in primary aldosteronism.

The release of arginine vasopressin (AVP) and atrial natriuretic hormone (ANH) and their involvement in renal water and electrolyte metabolism in primary aldosteronism in humans were studied. An oral acute water load (20 ml/kg body weight) was given to each of 12 patients before and after surgical removal of their aldosterone-producing adenoma(s). Plasma AVP and ANH were measured simultaneously, and renal water and electrolyte metabolism and tubular functions were determined. The same water load was given to seven normal subjects and the same parameters were determined. In the presence of mineralocorticoid excess before the operation, plasma AVP was relatively low compared with plasma osmolality (Posm), but was not suppressed in response to decreases in Posm after the water load. Baseline plasma ANH was high and increased further after the water load; urinary dilution and diuresis both remained normal. After the operation, baseline plasma AVP was normal and decreased in response to the decrease in Posm after the water load, with normal urinary dilution and diuresis. Baseline plasma ANH was normal, and did not increase after the water load. The ratio of urinary K and Na clearances and distal tubular reabsorption of Na increased before the operation. These results suggest that there are perturbations of AVP and ANH release in primary aldosteronism, despite the normal urinary dilution after a water load.

Effect of pericardiocentesis on circulating concentrations of atrial natriuretic hormone and arginine vasopressin in dogs with spontaneous pericardial effusion

Factors regulating the secretion of atrial natriuretic hormone (ANH) and arginine vasopressin (AVP) have not been elucidated fully. In several studies the release of these peptides has been studied by inducing both increased atrial pressure and atrial distension. A few studies employ cardiac tamponade, allowing the effect of atrial pressure and atrial stretch to be studied separately. In eleven dogs with spontaneous cardiac tamponade the effect of pericardiocentesis on circulating concentrations of ANP and AVP was studied. Pericardiocentesis was followed by a prompt rise in (non-elevated) plasma ANH concentrations from 21.6 +/- 7.3 to 65.4 +/- 17.1 pmol/l (mean +/- SEM). The initially slightly elevated AVP concentration of 5.5 +/- 1.5 pmol/l declined following pericardiocentesis to 2.1 +/- 0.5 pmol/l. In three dogs the systolic arterial pressure was measured indirectly and the central venous pressure was measured with a fluid-filled catheter. Before and after pericardiocentesis arterial pressure readings did not change significantly. Central venous pressure values showed an immediate very steep significant decrease after centesis. It is concluded that ANH release is primarily regulated by stretch and not by atrial pressure, that plasma AVP concentrations are moderately elevated in cardiac tamponade and that in cardiac tamponade pericardiocentesis causes a rapid decline in plasma AVP concentration.

Effects of a nitric oxide synthase inhibitor on vasopressin and atrial natriuretic hormone release, thermogenesis and cardiovascular functions in response to interleukin-1 beta in rats.

To assess whether nitric oxide (NO) formed by IL-1 beta affects vasopressin (AVP) and atrial natriuretic hormone (ANH) release and the regulation of blood pressure and body temperature, intravenous infusion of either N omega-nitro-L-arginine methyl ester (L-NAME) alone (50 micrograms/kg.body weight.min for 135 min), human recombinant interleukin 1 beta (IL-1 beta) alone (750 ng/kg.body weight.min for 120 min), or L-NAME (50 micrograms/kg.body weight.min for 135 min) with IL-1 beta (750 ng/kg.body weight.min for 120 min), was performed following priming doses of L-NAME (2 mg/kg.body weight) and IL-1 beta (7.5 micrograms/kg.body weight) into conscious rats (n = 6 each). In the control group, saline alone was administered. Plasma AVP and ANH, mean arterial blood pressure (MABP), heart rate (HR) and rectal temperature (RT) were determined. In response to L-NAME, plasma AVP significantly increased, but plasma ANH did not change, despite increases in MABP and decreases in HR. In response to IL-1 beta, both plasma AVP and ANH increased with decreases in MABP and RT without any changes in HR. With L-NAME and IL-1 beta, both plasma AVP and ANH increased, and depressor response to IL-1 beta was partly attenuated by L-NAME, without any changes in RT. With saline alone, none of these parameters changed during the study. These results suggest that NO may directly affect the release of AVP and ANH and the regulation of body temperature and blood pressure, but NO formed by IL-1 beta may not have direct effects on the release of these hormones, and the regulation of blood pressure and temperature.

Effects of interleukin-1 beta on blood pressure, thermoregulation, and the release of vasopressin, ACTH and atrial natriuretic hormone.

To assess how interleukins (IL) affect the release of vasopressin (AVP), atrial natriuretic hormone (ANH), and ACTH and the regulation of blood pressure (BP), heart rate (HR) and rectal temperature (RT), the 3 doses of 1.73 (low dose, LD), 8.63 (medium dose, MD), and 43.16 pmol/100 gBW (high dose, HD) of human recombinant IL-1 beta were intravenously (iv) administered in conscious rats, and plasma AVP, ANH, and ACTH, BP, HR and RT were determined simultaneously. In the control group (CON), the drug was omitted. Circulatory IL-1 beta levels were determined in each dose, and indomethacin (1 mg/rat, IM) was administered iv in the HD and CON groups. Plasma IL-1 beta increased transiently following IL-1 beta administration in each group. Plasma AVP, ANH, and ACTH increased in the LD, MD, and HD groups, respectively. Mean arterial BP (MABP) and RT increased in the LD group, but HR did not change. In the MD and HD groups, MABP decreased at 30 min followed by its increase at 120 min, but RT in both groups decreased. In the CON group, these parameters did not change. IM attenuated plasma AVP and ACTH responses to HD and also inhibited decreases in MABP and RT. These results suggest that IL-1 beta affects the release of AVP and ACTH, blood pressure and thermogenesis via prostaglandins (PGs), but ANH release related to IL-1 beta may not be mediated by PGs.

Role of vagal nerves and atrial natriuretic hormone in vasopressin release and a diuresis under hypertonic volume expansion.

To assess whether increases in circulating atrial natriuretic hormone (ANH) in response to the plasma volume expansion, besides the volume receptor-mediated mechanisms, attenuate the arginine vasopressin (AVP) response to increased plasma osmolality and whether changes in plasma AVP and ANH affect renal solute excretion under hypertonic plasma volume expansion, hypertonic saline (0.95 mol/l saline) alone, hypertonic saline with 6% dextran (6D-HS) and hypertonic saline with 9% dextran (9D-HS) were administered into anesthetized dogs. In the control study, 0.15 mol/l NaCl alone was administered. Plasma AVP and ANH and cardiovascular and renal functions were determined. Hypertonic saline and 9D-HS also were administered into the vagotomized and sham operated dogs, and the same parameters were determined. Mean blood pressure and heart rate never changed in all the groups, but central venous pressure and plasma volume increased markedly in 6D-HS and 9D-HS groups. In the control and hypertonic saline groups, central venous pressure increased slightly but plasma volume never changed. Plasma AVP increased in the order of hypertonic saline, 6D-HS and 9D-HS, but plasma ANH increased in reverse order. Vagotomy restored the AVP response to 9D-HS to 75% of its response to hypertonic saline, with a marked rise in plasma ANH. Urine sodium and potassium excretion and urine flow increased in hypertonic saline, 6D-HS and 9D-HS groups, but these increases were comparable among the groups. In the control group, these parameters never changed. These results suggest that the volume receptor-mediated vagal neural and ANH responses to the plasma volume expansion may have an effect on the suppression of the AVP response to osmotic stimuli, and increased plasma ANH release never potentiated the natriuresis under the hypertonic plasma volume expansion.

Plasma vasopressin and atrial natriuretic hormone levels in hypopituitarism with and without hydrocortisone treatments: responses to an acute water load

To assess whether arginine vasopressin and atrial natriuretic hormone participate in impaired urinary dilution and excretion in glucocorticoid deficiency secondary to hypopituitarism, an acute oral water load of 20 ml.kg-1 BW was undertaken in the absence and presence of an oral hydrocortisone (60 mg) treatment in patients with ACTH deficiency (N = 7) and panhypopituitarism (N = 2). Plasma arginine vasopressin and atrial natriuretic hormone and renal water handling were simultaneously determined and compared with those in similarly water-loaded normal subjects. Plasma arginine vasopressin did not fall in response to decreased blood osmolality after an acute water load in the absence of hydrocortisone; plasma atrial natriuretic hormone did not change despite blood volume expansion; and impairment in urinary dilution and excretion remained. On the other hand, in the presence of hydrocortisone, plasma arginine vasopressin fell in response to a decrease in plasma osmolality and plasma atrial natriuretic hormone increased, thereby restoring urinary dilution and excretion. These results demonstrate that the impaired arginine vasopressin response to acute water loading play an essential role in deranged renal water and electrolyte handling in the state of glucocorticoid deficiency; the impaired release of atrial natriuretic hormone also may affect these disorders.

Effect of right atrial appendectomy on the release of atrial natriuretic hormone

Atrial natriuretic hormone is released from the right atrial appendage in response to atrial distention. During cardiac operations the right atrial appendage is usually partially removed or ligated for venous cannulation. To evaluate the effect of right atrial appendectomy on the release of atrial natriuretic hormone and its natriuretic and diuretic responses, we prospectively randomized into two groups 23 patients undergoing elective coronary artery bypass operations. There were 16 male and 7 female patients with a mean age of 62 +/- 7 years. Group A (n = 11) had the right atrial appendage removed, and group B (n = 12) had the right atrial appendage preserved and venous cannulation done lateral to the appendage. The two groups were comparable for sexual distribution, age, number of grafts, and extracorporeal bypass time. All patients had normal left ventricular and renal functions, and they did not receive any diuretics during the study period. The patients were studied both preoperatively and postoperatively whereby the atrial natriuretic hormone serum levels, urine volume per minute, fractional excretion of sodium, amount of sodium excreted, and central venous pressure were measured before and after volume expansion with 5% albumin, 7.5 ml/kg. There was no statistical difference in these parameters preoperatively. In the postoperative period, however, group B patients had higher atrial natriuretic hormone levels after volume expansion than group A patients (376 +/- 84 versus 184 +/- 31 pg/ml; p less than 0.05), higher urine volume per minute (4.4 +/- 1.0 versus 2.0 +/- 0.4 ml/min; p less than 0.05), higher fractional excretion of sodium (2.30 +/- 0.66 versus 0.64 +/- 0.19; p less than 0.02), and higher amount of sodium excreted (511.1 +/- 150.9 versus 83.9 +/- 22.8 mmol/min; p less than 0.02). The central venous pressure was similar both before (9 +/- 1 versus 9 +/- 1 mm Hg) and after (16 +/- 1 versus 15 +/- 1 mm Hg) volume expansion in both groups. We conclude that preserving the right atrial appendage during cardiac operations significantly increased the release of atrial natriuretic hormone, resulting in increased urinary sodium excretion and better diuresis in the postoperative period.