Pregnant rats are refractory to the natriuretic actions of atrial natriuretic peptide

1994 ◽  
Vol 267 (6) ◽  
pp. R1611-R1616 ◽  
Author(s):  
S. Masilamani ◽  
L. Castro ◽  
C. Baylis
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Volume Expansion ◽  
Renal Plasma Flow ◽  
Pregnant Rats ◽  
Arterial Blood ◽  
Renal Vascular ◽  
Renal Responses ◽  
Percent Decline ◽  
Atrial Natriuretic

Normal pregnant women and rats undergo a volume expansion. Atrial natriuretic peptide (ANP) is involved in volume homeostasis and is stimulated in response to volume expansion in nonpregnant animals, resulting in natriuresis and diuresis. The conscious, chronically catheterized rat was used to measure mean arterial blood pressure (MABP) and renal responses to administered ANP (160 ng.kg-1.min-1 i.v.) to determine if the actions of ANP are altered by pregnancy. These experiments examined virgin (n = 7) and pregnant rats, studied on gestational days 7-9 (n = 9) and 15-17 (n = 7). Renal clearance studies (with inulin and p-aminohippurate) were conducted in control conditions and during 60 min of ANP infusion. After the ANP infusion, plasma ANP concentrations were measured in virgin and pregnant rats. MABP fell with ANP infusion to similar absolute values in virgins (112 +/- 2 to 80 +/- 6 mmHg), 7- to 9-day pregnant (114 +/- 2 to 91 +/- 3 mmHg), and 15- to 17-day pregnant (107 +/- 2 to 88 +/- 4 mmHg) rats although the percent decline in MABP in 15- to 17-day pregnant rats was less than in virgins. Plasma ANP concentrations were similar in all groups. ANP had no effect on glomerular filtration rate, renal plasma flow, or renal vascular resistance in virgin or pregnant rats. ANP increased sodium excretion in virgins and in 7- to 9-day pregnant rats (+102 +/- 27 and +135 +/- 47%, respectively) but not in 15- to 17-day pregnant animals (+23 +/- 22%).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial natriuretic peptide and blunted renal responses to volume expansion in rats with Heymann nephritis

1993 ◽  
Vol 11 (5) ◽  
pp. S218???S219 ◽  
Author(s):  
Jean-Pierre Valentin ◽  
Wei-Zhong Ying ◽  
Leonardo A. Sechi ◽  
Michael H. Humphreys
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Volume Expansion ◽  
Heymann Nephritis ◽  
Renal Responses ◽  
Atrial Natriuretic

Atrial natriuretic peptide induces sustained natriuresis in conscious dogs

1990 ◽  
Vol 258 (6) ◽  
pp. R1445-R1452
Author(s):  
H. L. Mizelle ◽  
D. A. Hildebrandt ◽  
C. A. Gaillard ◽  
M. W. Brands ◽  
J. P. Montani ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Renal Excretion ◽  
Renal Plasma Flow ◽  
Conscious Dogs ◽  
Change In Mean ◽  
Renal Responses ◽  
Atrial Natriuretic

Although acute infusions of atrial natriuretic peptide (ANP) often cause natriuresis, these effects are not sustained, possibly because of reductions in arterial pressure or other compensatory adaptations. The aim of this study was to determine whether physiological increases in intrarenal ANP levels cause sustained natriuresis if changes in arterial pressure and other neurohumoral influences that might obscure the renal responses are controlled. Changes in renal function were quantitated during chronic unilateral renal arterial infusion of ANP at rates of 1, 2, and 4 ng.kg-1.min-1 in conscious dogs (n = 7) with the urinary bladder split to allow continuous measurement of renal excretion in the ANP-infused and contralateral, vehicle-infused kidneys. There was no change in mean arterial pressure at any infusion rate. During 1 ng.kg-1.min-1 infusion of ANP for 5 days, the renal excretory responses were small and variable. However, during 2 and 4 ng.kg-1.min-1 ANP infusion for 7 days, sodium excretion averaged 37.2 +/- 10.0 and 134.8 +/- 19.0% greater, respectively, in the ANP-infused kidneys compared with the vehicle-infused kidneys but there were no changes in glomerular filtration rate or effective renal plasma flow. These results demonstrate that when compensatory changes in arterial pressure and neurohumoral factors are controlled, ANP, at physiological concentrations, causes marked increases in renal excretion. This study supports the concept that ANP's effects to increase renal excretory capability could play a role in long-term control of arterial pressure and body fluid homeostasis.

Effects of human atrial natriuretic peptide on renal function and vasopressin release

1986 ◽  
Vol 250 (5) ◽  
pp. R789-R794 ◽  
Author(s):  
T. Kimura ◽  
K. Abe ◽  
M. Shoji ◽  
K. Tsunoda ◽  
K. Matsui ◽  
...  
Keyword(s):  
Renal Function ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Renal Plasma Flow ◽  
Free Water ◽  
Free Water Clearance ◽  
Vasopressin Release ◽  
Arterial Blood ◽  
Control Study ◽  
Atrial Natriuretic

To assess the effects of atrial natriuretic peptide (ANP) on the renal function, cardiovascular system, renin-angiotensin-aldosterone system, and vasopressin release, synthetic human ANP (alpha-hANP) was administered at a dose of 0.08 microgram X kg-1 X min-1 iv for 40 min into anesthetized dogs (n = 6). In the control study (n = 6), saline alone was infused. alpha-hANP brought about a significant increase in renal plasma flow, urinary Na and K output, urine flow, and osmolar clearance and a significant decrease in urinary osmolality, free water clearance, and filtration fraction (FF), with no changes in glomerular filtration rate. Plasma Na concentrations and osmolality did not change significantly, but plasma K concentrations fell progressively. Mean arterial blood pressure decreased without any changes in heart rate. Plasma renin activity (PRA), plasma aldosterone concentrations (PAC), and plasma vasopressin concentrations did not rise, but rather PRA and PAC tended to fall during alpha-hANP infusion. In the control study, there were no changes in these parameters except a progressive fall in FF and plasma K concentrations. These results indicate that the alpha-hANP-induced increase in renal blood flow plays an important role in producing natriuresis, but vasopressin may not be involved in the process of diuresis.

Role of insulin and atrial natriuretic peptide in sodium retention in insulin-treated IDDM patients during isotonic volume expansion

Diabetes ◽  
1990 ◽  
Vol 39 (3) ◽  
pp. 289-298 ◽  
Author(s):  
R. Trevisan ◽  
P. Fioretto ◽  
A. Semplicini ◽  
G. Opocher ◽  
F. Mantero ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Volume Expansion ◽  
Sodium Retention ◽  
Atrial Natriuretic

Brain Atrial Natriuretic Peptide Neurons Play an Essential Role in Volume Expansion-Induced Release of Atrial Natriuretic Peptide and Natriuresis

1993 ◽  
Vol 58 (6) ◽  
pp. 696-700 ◽  
Author(s):  
José Antunes-Rodrigues ◽  
Domingos W.L. Picanco-Diniz ◽  
Ana L.V. Favaretto ◽  
Jolanta Gutkowska ◽  
Samuel M. McCann
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Volume Expansion ◽  
Essential Role ◽  
Atrial Natriuretic

Effect of atrial natriuretic peptide on renal hemodynamics and sodium excretion during human pregnancy

1996 ◽  
Vol 271 (1) ◽  
pp. F239-F242 ◽  
Author(s):  
D. W. Irons ◽  
P. H. Baylis ◽  
J. M. Davison
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Late Pregnancy ◽  
Before And After ◽  
Basal Plasma ◽  
Renal Clearances ◽  
Atrial Natriuretic

The effect of infused atrial natriuretic peptide (ANP) on sodium excretion (UNa), glomerular filtration rate (GFR), and effective renal plasma flow (ERPF) was studied in 12 normotensive primigravidae at 32 wk gestation [late pregnancy (LP)] and again 4 mo postpartum [nonpregnant (NP)]. Three 20-min steady-state (renal) clearances of inulin and p-aminohippurate were used to measure GFR and ERPF, respectively, before and after infusion of ANP at 2 pmol.kg-1.min-1. Basal plasma ANP (pANP) was increased in LP compared with NP [7.8 +/- 0.6 vs. 3.3 +/- 0.4 pmol/l (P < 0.0001), respectively]. In LP, infusion of ANP increased pANP from 7.8 +/- 0.6 to 21.8 +/- 1.4 pmol/l (P < 0.00001), which produced a natriuresis [UNa of 0.18 +/- 0.02 vs. 0.25 +/- 0.03 mmol/min (P = 0.03), respectively], with no change in GFR (153 +/- 13 vs. 142 +/- 8 ml/min, P = 0.16) but a significant reduction in ERPF (766 +/- 52 vs. 660 +/- 31 ml/min, P = 0.002). In NP, ANP infusion increased pANP from 3.3 +/- 0.4 to 27.7 +/- 2.5 pmol/l (P < 0.00001), which produced no significant natriuresis [UNa of 0.22 +/- 0.07 vs. 0.26 +/- 0.09 mmol/min (P = 0.15), respectively] and no change in GFR (87 +/- 3 vs. 89 +/- 3 ml/min), but again a reduction in ERPF (486 +/- 17 vs. 414 +/- 9 ml/min, P < 0.001).

Adenosine modulates hypoxia-induced atrial natriuretic peptide release in fetal sheep

1995 ◽  
Vol 269 (1) ◽  
pp. H282-H287 ◽  
Author(s):  
D. A. Ogunyemi ◽  
B. J. Koos ◽  
C. P. Arora ◽  
L. C. Castro ◽  
B. A. Mason
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Fetal Hemoglobin ◽  
Blood Gases ◽  
Fetal Sheep ◽  
Control Value ◽  
Fetal Plasma ◽  
Arterial Blood ◽  
The Right ◽  
Atrial Natriuretic

The effects of adenosine on atrial natriuretic peptide (ANP) secretion were determined in chronically catheterized fetal sheep (> 0.8 term). Adenosine was infused into the the right jugular vein for 1 h at 8 +/- 0.4 (5 fetuses), 160 +/- 8 (6 fetuses), and 344 +/- 18 micrograms.min-1.kg estimated fetal wt-1. Fetal arterial blood gases and pH were generally unaffected by adenosine, although mean arterial CO2 tension increased transiently by 2-5 Torr and pH fell progressively during the highest rate of infusion. During the intermediate and high infusion rates, fetal hemoglobin concentrations increased by 11-13% and mean fetal heart rate rose by 18% from a control value of approximately 167 beats/min. Mean arterial pressure was not affected during adenosine infusion. Adenosine significantly increased fetal plasma ANP levels, with maximum concentrations 1.80, 2.36, and 2.51 times greater than control means (142-166 pg/ml) for the respective infusion rates of 8, 160, and 344 micrograms.min-1.kg estimated fetal wt-1. In seven fetuses, reducing fetal arterial O2 tension by approximately 9-10 Torr from a control of 23 +/- 1.3 Torr increased plasma ANP concentrations approximately 2.4 times the control mean of 176 pg/min. Adenosine-receptor blockade with 8-(p-sulfophenyl)-theophylline reduced by 50% the maximum hypoxia-induced rise in plasma ANP concentrations. It is concluded that adenosine causes a dose-dependent rise in fetal plasma ANP concentrations and modulates fetal ANP release during hypoxia.

Atrial Natriuretic Peptide: Regulator of Chronic Arterial Blood Pressure

Physiology ◽  
2000 ◽  
Vol 15 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Luis Gabriel Melo ◽  
Stephen C. Pang ◽  
Uwe Ackermann
Keyword(s):  
Blood Pressure ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Salt Intake ◽  
Gene Knockout ◽  
Renin Angiotensin System ◽  
Angiotensin System ◽  
Arterial Blood ◽  
Gene Knockout Mouse ◽  
Atrial Natriuretic

Recent findings in atrial natriuretic peptide (ANP) transgenic and gene knockout mouse models uncovered a tonic vasodilatory effect of this hormone that contributes to chronic blood pressure homeostasis. With elevated salt intake, ANP-mediated antagonism of the renin-angiotensin system is essential for blood pressure constancy, suggesting that a deficiency in ANP activity may underlie the etiology of sodium-retaining disorders.

scholarly journals Effects of Environmental Temperature on Atrial Natriuretic Peptide (ANP) -granules of Auricular Cardiocytes and Plasma ANP Level in Pregnant Rats

1993 ◽  
Vol 42 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Hiroharu MIFUNE ◽  
Syusaku SUZUKI ◽  
Kiyoshi NOKIHARA ◽  
Yuta KOBAYASHI ◽  
Tomoyuki UEDA ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Environmental Temperature ◽  
Pregnant Rats ◽  
Atrial Natriuretic
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