Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the effect of negative pressure breathing during the inspiratory phase only (intermittent NPB) in 9 healthy male subjects who were in a sitting position and had no food or fluid intake for 12 h before the study. Intermittent NPB was without effect on urine flow and urinary sodium excretion but caused a significant increase in creatinine clearance. Plasma renin activity was significantly reduced, whereas plasma antidiuretic hormone (ADH), atrial natriuretic factor (ANF), and aldosterone levels were unaffected. To determine whether the blunted urinary response to intermittent NPB was a postural phenomenon, the study was repeated in 6 of the subjects while supine. Under these conditions there was a significant increase in urine flow and plasma ANF levels, but no change in all other measured variables. These results are consistent with a role for ANF, but not ADH, in the diuresis seen in supine subjects during NPB.
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PMID:Effect of inspiratory-phase negative pressure breathing on urine flow in man. 153 61

The effects of two oral doses of zabicipril, a new angiotensin converting enzyme inhibitor, on systemic (arterial pressure, heart rate, and cardiac output) hemodynamic parameters and regional (brachial, carotid and femoral arteries' diameters and flows) hemodynamic parameters and on biologic (plasma-converting enzyme and renin activities, catecholamines, and atrial natriuretic factor) parameters were noninvasively investigated and compared with those of a placebo in a double-blind crossover study performed in six healthy male volunteers. Although it did not affect the systemic hemodynamic parameters, zabicipril induced a strong peripheral vasodilation, significantly reducing brachial, carotid, and femoral resistances and increasing the corresponding blood flows from 3 or 4 1/2 hours to 9 hours. This vasodilation affected only the arterioles, not the large arteries, and resulted in a redistribution of cardiac output toward the three regional vascular beds. Zabicipril induced an early, potent, and long-lasting converting enzyme inhibition. Furthermore, zabicipril did not affect plasma catecholamines and atrial natriuretic factor.
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PMID:Systemic and regional hemodynamic effects of zabicipril in healthy volunteers. 153 52

The volume regulating hormones were studied during a 4-week head-down tilt (CNES HDT) in five subjects with and without (controls) lower body negative pressure (LBNP). LBNP was applied 3 times a day for 3 weeks, 4 times a day for 4 d, and 6 times a day for 3 d the last week. In both groups we observed a significant decrease in body weight (3% in controls, 0.8% in LBNP), a significant increase in plasma renin activity and aldosterone (with an amplification of their rhythms), and a significant decrease in norepinephrine with no difference between the two groups. The only major hormonal difference was observed for atrial natriuretic factor (ANF), which decreased significantly in the control group and increased in the LBNP group. These results are compared with the improvement in orthostatic tolerance (OT) after HDT in the LBNP group in the same protocol (17). We conclude that many factors could be involved in the improvement of OT. The results suggest that better conservation of plasma volume in the LBNP group might have prevented a decrease in ANF. Whether ANF plays a role in the regulation of baroreceptor reflex with an improvement in OT is currently unknown.
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PMID:Results of a 4-week head-down tilt with and without LBNP countermeasure: I. Volume regulating hormones. 153 8

Time course of multiple hemodynamic changes in rats after opening an AV fistula was assessed. The fistula was made in male Sprague-Dawley rats by anastomosing the aorta and vena cava below the renal arteries. At 1 h (1H), 1 day (1D), 1 wk (1W) and 5 wk (5W) in sham controls or after opening an AV fistula, we measured cardiac output (CO) and tissue flows by using radioactive microspheres. The flow of microspheres to the lungs was used as a measure of shunt flow. In the fistula animals this lung flow (fistula flow) was 50-77% of the CO compared with 1-3% in the control animals. Cardiac index in the fistula animals increased by 40, 107, 129, and 307% compared with the respective control animals in the consecutive time groups. Systemic flow, tissue flows, and mean arterial blood pressure (MAP) in the fistula animals in the 1H and 1W groups were significantly decreased below control values, but each of these variables returned to control levels after 5W. Hematocrit (Hct) significantly decreased, whereas right atrial pressure (RAP) gradually increased over the experimental period. These two observations suggest retention of fluid. Plasma renin activity increased in the 1H animals but returned to control in the 1D animals. Atrial natriuretic peptide (ANP) gradually increased throughout the 5 wk from 86 +/- 22 (1H) to 709 +/- 217 pg/ml (5W). The increase in ANP correlated with the increase in RAP. Calculated total peripheral resistance in fistula animals was significantly decreased throughout the experiments.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hemodynamic changes in rats after opening an arteriovenous fistula. 153 95

Normothermic cardiopulmonary bypass (CPB) is used in cardiac surgery at some institutions. To compare hemodynamic and hormonal responses to hypothermic (29 degrees C) and normothermic nonpulsatile CPB, 20 adults undergoing coronary artery bypass graft and/or aortic valve replacement were studied. Hemodynamic measurements and plasma hormone concentrations were obtained from preinduction to the third postoperative hour. The two groups were given similar amounts of anesthetics and vasodilators. Systemic vascular resistance increased only during hypothermic CPB, and heart rate was higher at the end of hypothermic CPB. Postoperative central venous pressure and pulmonary capillary wedge pressure were lower after hypothermic CPB. Oxygen consumption decreased by 45% during hypothermic CPB, did not change during normothermic CPB, but increased similarly in the two groups after surgery; mixed venous oxygen saturation (SvO2) was significantly lower during normothermic CPB. Urine output and composition were similar in the two groups. In both groups, plasma epinephrine, norepinephrine, renin activity, and arginine vasopressin concentrations increased during and after CPB. However, epinephrine, norepinephrine, and dopamine were 200%, 202%, and 165% higher during normothermic CPB than during hypothermic CPB, respectively. Dopamine and prolactin increased significantly during normothermic but not hypothermic CPB. Atrial natriuretic peptide increased at the end of CPB and total thyroxine decreased during and after CPB, with no difference between groups. This study suggests that higher systemic vascular resistance during hypothermic CPB is not caused by hormonal changes, but might be caused by other factors such as greater blood viscosity. A higher perfusion index during normothermic CPB might have allowed higher SvO2.
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PMID:Hemodynamic and hormonal responses to hypothermic and normothermic cardiopulmonary bypass. 156 99

The purpose of the present study was to determine whether variations in salt intake would alter the plasma concentrations of atrial natriuretic factor and the N-terminal atrial natriuretic factor prohormone peptides proANF 1-98 and proANF 31-67. Two groups of rats were placed on different salt intakes for 1 week. The low salt group of rats was fed a diet providing less than 0.1 mM NaCl/day and given deionized water to drink. The normal salt group of rats was fed regular rat chow with deionized water to drink, providing them with approximately 2 mM NaCl/day. Plasma atrial natriuretic factor was 204 +/- 60 pg/ml (mean +/- SE) in normal salt rats and was significantly lower in the low salt group (44 +/- 13 pg/ml, P less than 0.01). ProANF 1-98 was also significantly higher in the normal salt group (635 +/- 47 pg/ml) compared with the low salt group (353 +/- 33 pg/ml, P less than 0.01). ProANF 31-67 was 123 +/- 21 pg/ml in the normal salt group and 59 +/- 12 pg/ml in the low salt group (P less than 0.05). Plasma renin activity in ng angiotensin l/ml/hr averaged 1.80 +/- 0.15 in the normal salt group of rats and was significantly higher in the low salt group of rats (5.66 +/- 1.07, P less than 0.05). These results suggest that atrial natriuretic factor and the atrial natriuretic factor prohormones may play a role in the physiological adjustments to low salt intake.
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PMID:Effect of changes in sodium intake on atrial natriuretic factor (ANF) and peptides derived from the N terminus of the ANF prohormone in the rat. 153 86

Seven normal subjects underwent sequential 20-min infusion of arginine vasopressin (AVP) at 0.5 and 2 ng/(kg.min) and a complete right-side heart hemodynamic evaluation during the study to analyze the effect of this hormone on atrial natriuretic factor (ANF) secretion in humans and to elucidate whether this effect was primary or secondary to the hemodynamic or hormonal changes induced by AVP. Plasma ANF levels increased at the end of the first (P less than 0.05) and second (P less than 0.01) infusion periods. No significant changes in mean arterial, pulmonary artery, right and left atrial pressures were recorded during the study. Cardiac output (P less than 0.05) and heart rate (P less than 0.05) decreased, while total vascular resistances (P less than 0.05) increased with respect to basal values in both infusion periods. Plasma renin activity decreased (P less than 0.01) at the end of the infusion, while plasma aldosterone, epinephrine and norepinephrine showed no significant changes. We conclude that arginine vasopressin increases plasma ANF levels in humans and that this effect cannot be ascribed to hemodynamic or hormonal changes induced by this hormone, suggesting a direct effect of vasopressin on the atrial myocyte.
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PMID:Arginine vasopressin infusion increases plasma levels of atrial natriuretic factor in humans. 153 5

To analyze the determinants of left ventricular (LV) performance (myocardial afterload, chamber size, mass, and contractility) in Goldblatt hypertension, 19 anesthetized one-kidney, one-clip (1K1C) and 28 two-kidney, one-clip (2K1C) male Wistar rats were studied 58 to 62 days after clipping, together with 19 sham-operated and 13 normal rats (controls), by M-mode echocardiography using necropsy-validated methods of measurement. The LV fractional shortening was inversely related to end-systolic stress in all groups (r = -0.89 to -0.95, all P less than .00001): 7 2K1C (25%) and 9 1K1C (47%) had fractional shortening above the upper confidence limit in control animals. Both 1K1C and 2K1C with high LV performance had severe hypertension, inadequate LV hypertrophy, with resultant high wall stress (both P less than .005), increased LV chamber dimension (P less than .005 and P less than .05, respectively) and high afterload-corrected fractional shortening (both P less than .001); 2K1C also had high plasma renin activity and atrial natriuretic factor levels (both P less than .01). Rats with normal LV performance exhibited mild hypertension, adequate LV hypertrophy (normalizing wall stress), and normal LV chamber size and afterload-corrected fractional shortening. Thus, 8 1/2 weeks after clipping, adequate LV hypertrophy allows maintenance of normal LV function by normalizing myocardial afterload in a majority of rats with Goldblatt hypertension, whereas increased LV contractility (and possibly use of preload reserve in 1K1C) maintains normal LV function in the presence of inadequate LV hypertrophy and elevated wall stress, in a substantial minority of rats that developed more severe Goldblatt hypertension.
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PMID:Relation of left ventricular hypertrophy, afterload, and contractility to left ventricular performance in Goldblatt hypertension. 153 70

To examine the influence of an increase in central blood volume with head-out water immersion (WI) on fluid-regulating hormones during exercise, 10 healthy men underwent upright leg cycle exercise on land and with WI. Venous plasma renin activity and plasma venous concentrations of atrial natriuretic peptide, plasma aldosterone, and arginine vasopressin were determined at exercise intensities corresponding to approximately 40, 60, 80, and 100% peak oxygen consumption (VO2) and at minutes 1 and 5 of seated rest recovery within each environment. Peak VO2 did not differ on land and with WI. Atrial natriuretic peptide concentration was higher (P less than 0.05) and plasma renin activity was lower (P less than 0.05) in water than on land at 40% peak VO2 through minute 5 of recovery. Plasma aldosterone and arginine vasopressin concentrations were lower (P less than 0.05) in water at peak exercise and at minutes 1 and 5 of recovery. Osmolality and plasma sodium and potassium concentrations during exercise were similar in water and on land. The results indicate that WI alters the circulating levels of several hormones involved in fluid and electrolyte regulation during exercise. These hormonal alterations can best be explained by stimulation of low-pressure baroreceptors and atrial stretch due to increased central blood volume with head-out WI.
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PMID:Fluid-regulating hormones during exercise when central blood volume is increased by water immersion. 153 5

Hyponatremia is common following subarachnoid hemorrhage and has alternatively been attributed to either the inappropriate secretion of antidiuretic hormone or natriuresis causing intravascular volume contraction. We prospectively studied body sodium and intravascular volume regulation in 19 patients, beginning within 3 days after acute aneurysmal subarachnoid hemorrhage occurred, in order to determine the impact of hypervolemic therapy on both hyponatremia and volume contraction and to ascertain whether humoral factors account for hyponatremia. Serial measurements of plasma arginine vasopressin, atrial natriuretic factor, renin activity, aldosterone, and catecholamines were correlated with body sodium and fluid balance, change in blood volume, serum sodium concentration, and osmolality. Six patients (32%) developed hyponatremia, but only 2 had a negative sodium balance. In most patients, levels of atrial natriuretic factor were elevated, while plasma renin activity and aldosterone concentrations were generally suppressed. Plasma arginine vasopressin levels were not suppressed during hypo-osmolality and did not correlate with serum osmolality in hyponatremic patients. Only 1 patient had a decrease in blood volume, which was associated with marked rises in aldosterone and plasma renin activity, but normal serum sodium and plasma atrial natriuretic factor levels. We conclude that following subarachnoid hemorrhage: (1) Hypervolemic therapy prevents volume contraction but not hyponatremia, (2) humoral factors may favor both sodium loss and water retention, and (3) arginine vasopressin regulation is disturbed and may contribute to hyponatremia.
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PMID:Hypervolemic therapy prevents volume contraction but not hyponatremia following subarachnoid hemorrhage. 153 78


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