scholarly journals Effects of water deprivation on atrial natriuretic peptide secretion and density of binding sites in adrenal glands and kidneys of maternal and fetal rats in late gestation

1999 ◽  
pp. 160-168 ◽  
Author(s):  
S Deloof ◽  
C De Seze ◽  
V Montel ◽  
A Chatelain

The effects of water deprivation for 3 days were studied in pregnant rats and their fetuses on day 21 of gestation. Maternal water deprivation induced a significant decrease of the body weight in both maternal and fetal rats. This weight loss was accompanied by significant increases in plasma osmolality and haematocrit in both maternal and fetal rats. Similarly, dehydration significantly decreased plasma atrial natriuretic peptide (ANP) concentrations and increased plasma aldosterone concentrations in maternal and fetal rats. Water-deprived maternal rats presented a significant increase in total ANP receptor density in isolated renal glomeruli and adrenal zona glomerulosa membranes. This increase was due to a significant increase in ANPc receptor density in both renal glomeruli and adrenal zona glomerulosa. The densities of total ANP, ANPb and ANPc receptors in fetal kidneys and adrenal glands were not affected by maternal dehydration. These results suggest that the dehydrated maternal rat is able to up-regulate the number of its ANP receptors in its kidneys and adrenal glands, in response to a decrease in plasma ANP concentrations. In contrast, the fetal rat does not seem to be able to regulate its own ANP receptors in response to maternal dehydration, in spite of a decrease in plasma ANP concentrations.

1997 ◽  
Vol 155 (3) ◽  
pp. 523-530 ◽  
Author(s):  
P Vaillancourt ◽  
S Omer ◽  
R Palfree ◽  
DR Varma ◽  
S Mulay

The main objective of this study was to find out if the reported changes in the aldosterone-suppressant activity of atrial natriuretic peptide (ANP) during different hormonal states in rats are due to a modulation of ANP receptors. In zona glomerulosa cells, ribonuclease protection assay detected mRNAs for guanylate cyclase (GC)-coupled ANP GC-A and GC-B receptors, and for ANP C receptors, which are not coupled to GC. Western analysis using polyclonal anti-GC-A and anti-GC-B receptor antibodies revealed the presence of GC-A but not GC-B receptor proteins in zona glomerulosa cells. Pregnancy (days 7, 16 and 21), oestradiol-17 beta and progesterone decreased mRNAs for all the three ANP receptors in zona glomerulosa cells. Pregnancy decreased GC-A receptor proteins in zona glomerulosa cells, but these recovered to virgin values on day 2 postpartum. ANP receptor mRNAs in zona glomerulosa cells increased by postpartum day 2, but did not reach the values found in virgin rats. Zona fasciculata mainly contained GC-A receptor mRNA. It is concluded that ANP receptors in rat adrenal zona glomerulosa are modulated by pregnancy, oestrogen and progesterone; a decrease in ANP GC-A receptors during pregnancy might explain the accompanying decrease in the aldosterone-suppressant effects of ANP.


Endocrinology ◽  
2007 ◽  
Vol 148 (4) ◽  
pp. 1638-1647 ◽  
Author(s):  
Hirofumi Hashimoto ◽  
Hiroaki Fujihara ◽  
Makoto Kawasaki ◽  
Takeshi Saito ◽  
Minori Shibata ◽  
...  

Ghrelin is known as a potent orexigenic hormone through its action on the brain. In this study, we examined the effects of intracerebroventricular (icv) and iv injection of ghrelin on water intake, food intake, and urine volume in rats deprived of water for 24 h. Water intake that occurred after water deprivation was significantly inhibited by icv injection of ghrelin (0.1, 1, and 10 nmol/rat) in a dose-related manner, although food intake was stimulated by the hormone. The antidipsogenic effect was as potent as the orexigenic effect. Similarly, water intake was inhibited, whereas food intake was stimulated dose dependently after iv injection of ghrelin (0.1, 1, and 10 nmol/kg). The inhibition of drinking was comparable with, or even more potent than, atrial natriuretic peptide (ANP), an established antidipsogenic hormone, when administered icv, although the antidipsogenic effect lasted longer. ANP had no effect on food intake. Urine volume decreased dose relatedly after icv injection of ghrelin but not by ANP. Intravenous injection of ghrelin had no effect on urine volume. Because drinking usually occurs with feeding, food was withdrawn to remove the prandial drinking. Then the antidipsogenic effect of ghrelin became more potent than that of ANP and continued longer than when food was available. Expression of Fos was increased in the area postrema and the nucleus of the tractus solitarius by using immunohistochemistry after icv and iv injection of ghrelin. The present study convincingly showed that ghrelin is a potent antidisogenic peptide in rats.


1995 ◽  
Vol 269 (2) ◽  
pp. R245-R251 ◽  
Author(s):  
R. E. Blackburn ◽  
W. K. Samson ◽  
R. J. Fulton ◽  
E. M. Stricker ◽  
J. G. Verbalis

These studies evaluated the involvement of central oxytocin (OT) and atrial natriuretic peptide (ANP) receptors in the osmotic inhibition of hypovolemia-induced salt appetite. Rats were pretreated centrally with the A chain of the cytotoxin ricin conjugated to OT (rAOT) or ANP (rAANP) to selectively inactivate cells bearing these respective receptors, or rats were pretreated with the unconjugated A chain (rA) as a control. Hypovolemia was induced with subcutaneous colloid injections, and rats then were given either 2 M mannitol, which raises plasma osmolality but lowers plasma sodium, or 1 M NaCl, which raises both. Hypertonic mannitol inhibited saline ingestion in rA-treated control rats but stimulated ingestion in rAOT- and rAANP-treated rats, whereas hypertonic NaCl blunted saline ingestion in rA- and rAOT-treated rats but stimulated ingestion in rAANP-treated rats. Angiotensin II-induced saline intake was similarly potentiated in rAOT- and rAANP-treated rats, indicating that this treatment also activates central inhibitory OT and ANP pathways. These data suggest that central ANP receptors mediate both Na(+)- and osmolality-induced inhibition of NaCl ingestion, whereas central OT receptors primarily mediate osmolality-induced inhibition of NaCl ingestion in rats.


2004 ◽  
Vol 229 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Kyung Sun Lee ◽  
So Young Kim ◽  
Jeong Hee Han ◽  
Yun Ah Kim ◽  
Chunhua Cao ◽  
...  

1990 ◽  
Vol 259 (1) ◽  
pp. F130-F137
Author(s):  
E. Nuglozeh ◽  
G. Gauquelin ◽  
R. Garcia ◽  
J. Tremblay ◽  
E. L. Schiffrin

The receptor for atrial natriuretic peptide (ANP) in the rat renal papilla was characterized pharmacologically. After solubilization and irreversible binding with disuccinimidylsuberate, it was shown on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) to be made of a single peptide of 125 kDa. The regulation of the renal papillary ANP receptor was studied in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. DOCA-salt rats had suppressed plasma renin activity and increased plasma ANP concentrations (408 +/- 35 vs. 133 +/- 12 pg/ml in uninephrectomized controls, P less than 0.01). The renal papilla was hypertrophied in DOCA-salt hypertensive rats (93 +/- 1 vs. 52 +/- 1 mg, P less than 0.01). The density of ANP sites in the papilla was significantly higher in DOCA-salt rats (141 +/- 31 fmol/papilla) than in controls (34 +/- 8 fmol/papilla, P less than 0.01). Affinity of sites in DOCA-salt rats and controls was similar. The production of guanosine 3',5'-cyclic monophosphate (cGMP) in renal papilla in response to ANP was significantly higher in DOCA-salt rats. In contrast to the renal papillary ANP receptor, acid-washed vascular and glomerular ANP sites were significantly decreased in density in DOCA-salt hypertensive rats. In blood vessels and glomeruli, both the high- and low-molecular mass receptor (as detected on SDS-PAGE under reducing conditions) was proportionately decreased in density in DOCA-salt hypertensive rats. The present results suggest that an increased number of ANP receptors and exaggerated cGMP response to ANP in the renal papilla may underlie the increased natriuretic responsiveness of the kidney to ANP in DOCA-salt hypertensive rats.


1989 ◽  
Vol 30 (4) ◽  
pp. 613-613
Author(s):  
Masaki Kurihara ◽  
Kimihiro Yamashita ◽  
Masami Niwa ◽  
Kazuto Shigematu ◽  
Masayori Ozaki ◽  
...  

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