Endothelin-1(ET) is a recently discovered endothelium-derived vasoconstrictor peptide. Plasma concentrations of immunoreactive (IR-) endothelin were investigated in rats by radioimmunoassay after extraction of endothelin on Sep-Pak Cartridges. In control rats, a mean concentration of 1.03 +/- 0.2 pg/ml was found. After exercise performed until semi-exhaustion or exhaustion, the mean plasma ...

Under non-exercise conditions, atrial natriuretic peptide (ANP) elevation suppresses plasma renin activity (PRA) and aldosterone (PA). A similar effect of ANP on PRA-PA during exercise has been suggested but not demonstrated. We measured ANP, PRA, PA, plasma potassium (K+), and changes in plasma volume (PV) and blood volume (BV) at ...

We investigated the relationship between plasma atrial natriuretic polypeptide (ANP) levels and hemodynamic indices during dynamic exercise testing in 15 patients with effort angina pectoris. Patients exercised on an angina-limited, supine, multistage bicycle ergometer, and plasma ANP levels and hemodynamic indices were measured at rest, at peak exercise, and 6 ...

Investigations have shown the presence of a cardiodepressant factor in the fluid incubating the posterior pituitary lobe "in situ", which decreased contraction frequency of the isolated heart auricle (Acta Physiol. Pol., 1984, 35: 460-468). The influence on the spontaneous contraction frequency of the isolated heart auricle of the following synthetic ...

The response in terms of production of atrial natriuretic factor to maximal cardiopulmonary exercise was investigated in 13 patients with mild heart failure (New York Heart Association function class II) secondary to previous myocardial infarction. Exercise induced a rapid and gradually increasing production of atrial natriuretic factor. The concentration at ...

Acute saline volume expansion (VE) in the developing animal is associated with a blunted natriuretic response when compared with that in adults. Recent studies have suggested that renal interstitial hydrostatic pressure (RIHP) plays an important role in mediating VE-induced natriuresis in the adult. The purpose of our study was to ...

Changes in plasma levels of atrial natriuretic peptide (ANP) and albumin, and blood hematocrit (Hct) during treadmill exercise were studied in 6 healthy men before and after beta-adrenergic blockade. Plasma ANP levels increased during exercise and then gradually decreased. There was a concomitant increase in both Hct and plasma albumin ...

Prior studies have shown that circulating atrial natriuretic factor (ANF) increases during short-term exercise, but the mechanism controlling ANF release, as well as the effect of exercise training on ANF release, remains unclear. Fifteen healthy mongrel dogs underwent short-term exercise testing before and after a 12-week period of exercise training ...

The reproducibility of the plasma clearance of 99Tcm DTPA was studied in 26 patients under standardized conditions with the subject fasting and at rest. The coefficient of variation of duplicate measurements in patients with glomerular filtration rates (GRF's) ranging from 11-103 ml min-1 was 8%. Mean GFR following a breakfast ...

Plasma levels of atrial natriuretic peptide (ANP) were measured by radioimmunoassay in 43 non-dialyzed uremic patients at rest and during maximal exercise to assess the possible relationship between plasma ANP levels and cardiac function, as judged by M-mode echocardiography and exercise tolerance. Patients with poor exercise capacity (exercise time less ...

The role of hypothalamic adrenoceptors in the exercise-induced alterations of plasma norepinephrine (NE), epinephrine (E), and corticosterone concentrations was investigated in rats. Exercise consisted of strenuous swimming against a counter-current for 15 min. Before, during, and after swimming, blood samples were withdrawn through a permanent heart catheter for determination of ...

Eleven males were examined at rest and during submaximal exercise in 5 degrees C and 20 degrees C environments to determine if the norepinephrine (NE) and other physiological responses in the cold would be altered by eight weeks of training. Blood samples were obtained at the end of 15 minutes ...

We studied the effect of a synthetic norepinephrine precursor, L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on the total (conjugated and unconjugated) norepinephrine concentrations in the cerebrospinal fluid (CSF) of 6 parkinsonian patients with freezing phenomenon. The total norepinephrine concentrations in the CSF increased from 5- to 75-fold after treatment with L-threo-DOPS. The degree of ...

The present study in the anesthetized dogs was designed to test the hypothesis that atrial natriuretic factor (ANF) attenuates whole kidney tubuloglomerular feedback (TGF) mediated decreases in renal blood flow (RBF) and glomerular filtration rate (GFR) produced by hypertonic saline (HS). Secondly, as adenosine (AD) has been implicated as a ...

The present study examined the influence of angiotensin on total intravascular capacity. In eight anaesthetized pigs, splenectomy, carotid sinus denervation and cervical vagotomy were performed. Blood was drained from the venae cavae to an extracorporeal reservoir and returned to the right atrium at a constant rate so that changes in ...

The influence of acid-base status on plasma catecholamines during exercise was investigated in six healthy volunteers. Incremental exercise to 175 W was performed on a bicycle ergometer under four conditions: 1) control, 2) during forced hyperventilation (HV), 3) after pretreatment with acetazolamide (AZE), and 4) while breathing 4% CO2. Resting ...

A novel pituitary peptide, designated 7B2, was shown to be present in the adrenal gland. 7B2-like immunoreactivity was mainly localized in the adrenal medulla, similarly to NPY and VIP. In order to elucidate the neural and humoral regulation of adrenal 7B2, NPY and VIP content, Wister rats were treated with ...

Responses to atrial peptide (AP) were observed in cheek pouch arterioles of anesthetized golden hamsters (pentobarbital sodium, 70 mg/kg ip). Vessels for observation were selected on the basis of their functional status in relation to controlling the perfused capillary surface area. Local application of AP onto microvessels at a final ...

The purpose of this investigation was to test the hypothesis that supine exercise elicits a greater atrial natriuretic peptide (ANP) response than upright exercise because of higher atrial filling pressure attained in the supine posture. Plasma ANP concentration ([ANP]) was measured during continuous graded supine and upright exercise in eight ...

We compared changes in antecubital venous plasma levels of norepinephrine (NE) and peroneal nerve muscle sympathetic activity (MSA) during and after nitroprusside (NP)-induced hypotension in nine healthy volunteers. During NP, MSA increased at 98.7%/min, peaked at 4 min at 399 +/- 77% (SE) of base line, and then decreased, so ...

Based on cDNA sequence data for human brain natriuretic peptide (BNP) precursor (1), a radioimmunoassay (RIA) system highly specific to human BNP (hBNP) was developed and used to characterize immunoreactive (ir-) hBNP in cardiac atrium. Gel filtration of ir-hBNP in atrium indicated that ir-hBNP was mainly comprised of two molecular ...

Previous research established a relationship between circulating sulfoconjugated norepinephrine (NE-SO4) and oxygen consumption at various exercise intensities. In this study, the stability of the NE-SO4 response was examined during sustained exercise at a constant relative intensity. Seven trained men bicycled at 78 +/- 3% of their maximal O2 consumption for ...

The present study was designed to investigate the influence of exercise intensity and duration as well as of inspiratory oxygen content on plasma atrial natriuretic peptide concentration [( ANP]) and furthermore to compare ANP with the effect on aldosterone concentration [( Aldo]). Ten untrained male subjects performed a maximal exercise ...

Previous work from our laboratory has shown that (i) regular endurance exercise lowers blood pressure (BP), and (ii) acute exercise increases circulating levels of atrial natriuretic peptide (ANP). We hypothesised that increased ANP release may contribute to the antihypertensive effect of regular exercise. Using arterial and selective venous (coronary sinus ...

The effect of 50 and 150 mg cicletanine, a new vasodilator antihypertensive, on plasma atrial natriuretic peptide (ANP), cyclic GMP and antidiuretic hormone has been investigated at rest and during standardized exercise, in a double blind cross over study in healthy subjects. Exercise significantly increased in plasma ANP, cyclic GMP ...

To examine whether endogenous secretion of atrial natriuretic peptide (ANP) modifies the bronchomotor response to moderately strenuous exercise and, conversely, whether hyperpnea of exercise or bronchoconstriction alone modulates the release of ANP, we compared the rise in specific airway resistance and the rise in circulating immunoreactive ANP (IR-ANP) induced by ...

This study was undertaken to evaluate the effects of the supine posture, immersion, and swimming on hormones involved in the regulation of hydrosaline equilibrium. Plasma levels of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), plasma renin activity (PRA), and aldosterone (ALDO) were measured by radioimmunoassay in eight untrained young subjects ...

Recently two peptides consisting of amino acids (a.a.) 1-30 and 31-67 of the N-terminus of the 126 a.a. prohormone of atrial natriuretic factor (pro ANF), as well as atrial natriuretic factor (ANF, a.a. 99-126; C-terminus) were found to have vasodilatory and natriuretic properties. These peptides, as well as ANF, circulate ...

In seven patients with mild to moderate essential hypertension, the effect of a new angiotensin converting enzyme (ACE) inhibitor, cilazapril, on atrial natriuretic factor (ANF) was examined at rest and during exercise. The exercise protocol consisted of three fixed workloads (25, 50 and 75W) every 4 min with the use ...

The influence of physiological cardiac hypertrophy on the concentration of plasma atrial natriuretic peptide was studied in six male athletes and six normally active, matched control men. They were examined by echocardiography during a graded exercise test on a bicycle ergometer. Plasma atrial natriuretic peptide was measured at rest, at ...

Atrial natriuretic factor (ANF) might be beneficial in several cardiovascular disorders, but its poor oral absorption and rapid inactivation in vivo have so far prevented its use in therapeutics. We have assessed the role of enkephalinase (membrane metallo-endopeptidase, EC 3.4.24.11) in the in vivo inactivation of ANF in mice and ...

1. Simultaneously obtained arterial and venous plasma atrial natriuretic factor (ANF) concentrations were compared at supine rest and during graded dynamic leg exercise in 10 healthy male subjects (aged 33-51 years). 2. Arterial ANF concentrations ranged between 12 and 179 pg/ml and venous concentrations between 9 and 177 pg/ml. 3. ...

The purpose of the present study was to determine whether endogenous adenosine (ADO) participates in angiotensin II (AII)-induced decreases in heart rate (HR) and regulates AII-induced aldosterone (ALDO) release. To test these hypotheses we investigated: 1) the effects of ADO and AII on base-line HR and ALDO levels; 2) the ...

Potentiated adrenocorticotropin (ACTH) and cortisol responses occur after the second of two small hemorrhages (hems) spaced 24 h apart in the dog. To test whether increased responses of other hormones might be associated with this effect, we examined plasma renin activity (PRA), angiotensin II (ANG II), and vasopressin after paired ...

Neurotensin (NT) levels were examined in five aerobically untrained females aged 20-36 engaged in acute graded exercise testing. In addition to radioimmunoassay measurements, high pressure liquid chromatography was performed to further characterize plasma NT-like immunoreactivity (NTLI). Epinephrine (E), norepinephrine (NE), and lactate (L) responses were also determined. Exercise testing consisted ...

To study whether the release of atrial natriuretic factor (ANF) was altered in diabetic cardiac autonomic neuropathy (CAN), we determined plasma ANF concentrations during exercise and changes of posture in three groups of age- and sex-matched subjects (9 healthy subjects, 7 diabetic patients with CAN, and 7 diabetic patients without ...

In an attempt to investigate their relationships with plasma volume (PV), heart rate (HR), and other hormonal systems, plasma atrial natriuretic peptide (ANP) levels were determined in response to exercise in the heat, associated with dehydration and rehydration with various fluids. Five normal subjects underwent four 3-h experiments, in a ...

The factors associated with the exercise-induced increase in plasma atrial natriuretic peptide (ANP) have not been clearly established. Thus the purpose of the study was to further document the stimulus for the exercise-induced release of ANP and to examine the role of ANP in the control of hydromineral balance during ...

Dopexamine is a new dopamine receptor agonist which also inhibits the uptake of norepinephrine (NE) into sympathetic nerves. Dopexamine was infused intravenously (i.v.) in anesthetized dogs at a rate used for treatment of congestive heart failure (4 micrograms/kg/min) before and during i.v. infusions of NE (0.26 +/- 0.06 and 0.57 ...

Data in the literature concerning atrial natriuretic factor (ANF) physiology in the fetus and newborn, although limited, suggest significant activity during the perinatal period. To characterize further ANF physiology during this time, we documented immunoreactive ANF (IR-ANF) concentrations in the right and left atria before and immediately after birth as ...

To study the effects of myocardial ischemia on plasma atrial natriuretic peptide (ANP) levels, immunoreactive ANP levels in the pulmonary artery (ANP-PA) and femoral vein (ANP-V) were measured before and during percutaneous transluminal coronary angioplasty (PTCA). Ten patients (group 1), seven of whom had no symptoms during PTCA, maintained a ...

The effects of synthetic atrial natriuretic factor (ANF) on sodium reabsorption by deep and superficial proximal tubules were examined in the rat. In response to ANF infusion (4 micrograms/kg/hr), the urinary fractional excretion of sodium increased from 1.21% +/- 0.53% to 3.48% +/- 0.48%, p less than 0.05 (n = ...

Platelet free cytosolic calcium (PFCC) was measured in 21 healthy volunteers before and after cigarette smoking or physical exercise. The aim was to investigate whether acute blood pressure changes and increases in circulating levels of catecholamines and vasopressin modify PFCC. PFCC was determined using the Quin-2 method. Following cigarette smoking, ...

A number of endogenously produced opioid peptides interact with centrally and peripherally located specific receptors to form a widespread neuroendocrine system with many implications for human function. It is becoming increasingly evident that moderately high and high intensity exercise stimulate the release of the opioid peptide beta-endorphin to the circulation ...

The foregoing clearly indicates that there are tremendous differences in the responsiveness of the iris sphincters of different mammalian species to the miotic effects of PGs. The iris sphincter of cats and dogs contracts in response to PGF2 alpha, but not in response to other PGs, at concentrations that can ...

A double-blind crossover trial was carried out in 7 healthy male volunteers to investigate the effects of penbutolol and a placebo on plasma atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) levels before and after exercise. Each subject underwent several bicycle ergometric exercises lasting 6 min before and after the ...

Experiments were designed to study changes of blood levels of norepinephrine (NE) and epinephrine (E) and their possible role in metabolic adaptation to short-lasting physical exercise in calves. After a resting period for 5 min (I), animals walked on a treadmill for 10 min at a speed of 60 m/min, ...

Atrial natriuretic factor is reported to be elevated during and immediately following exercise and is thought to play a role in fluid homeostasis and cardiovascular regulation. The predominant stimuli for atrial natriuretic factor release during exercise appear to be increases in atrial pressures or atrial distension, both of which are ...

Radionuclide angiographic measurements of left ventricular ejection fraction were performed at rest and during exercise in 10 normal persons and 11 patients with coronary artery disease. Exercise was continued on a supine bicycle exercise table up to a symptom-limited maximum. Plasma levels of atrial natriuretic peptide (ANP) were also determined ...

The plasma concentration of atrial natriuretic polypeptide (ANP) was measured in nine patients with essential hypertension during two grades of exercise tests performed in the supine position on a bicycle ergometer. The plasma ANP concentration significantly increased from 97.0 +/- 19.2 pg/ml to 107.6 +/- 23.7 pg/ml (p less than ...