The Renin-Angiotensin-Aldosterone System in Mother and Fetus at Term

Godard, Claude; Gaillard, Rolf C.; Vallotton, Michel B.

doi:10.1159/000180741

Cited by 55 publications

(40 citation statements)

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“…Large fluctuations of PRA within the first 48 hr of postnatal life were also observed by others in human newborns (16) and in litters of puppies (9). The fact that individual PRA levels tend to increase even further until 48-72 hr after birth (10,16) suggests the role of postnatal stimulating factors.…”

Section: Discussionmentioning

confidence: 99%

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Plasma Renin Activity Related to Sodium Balance, Renal Function and Urinary Vasopressin in the Newborn Infant

Godard

Geering

et al. 1979

Pediatr Res

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Summary MATERIALS AND METHODSPlasma renin activity was determined in 25 healthy, full-term, newborn infants aged 1 day to 9 weeks. High values were found, the mean level at 1-2 days of life (24.8 +. 8.4 ng/ml/hr, SE) being significantly higher than the mean levels at 7-9 days (5.8 + 1.5) and at 4-9 weeks (8.1 f 13) (P < 0.05). No correlation was found between plasma renin activity and systolic blood pressure, hematocrit, creatinine clearance, serum sodium, or serum potassium. Plasma renin activity (log values) was inversely correlated with sodium intake (r = -0.58) or with urinary sodium ( r = -OM), and positively with urinary osmolality (r = 0.67). The correlations reached higher coefFicients if only infants aged 5 9 days were considered.In addition, vasopressin was measured by radioimmunoassay in the urine. The daily excretion was lower in newborn infants (9.4 f 1.6 ng/m2/day, SE, at 1-2 days of postnatal life) than in healthy children (37.1 + 5.6), and was significantly correlated with creatinine clearance ( r = 0.69), but not with urinary osmolality. SpeculationThe postnatal changes of plasma renin activity were significantly correlated only with parameters of sodium balance and with urinary osmolality, so that one can speculate that early after birth, the renin-angiotensin system plays a preponderant role not only in sodium homeostasis, but also in water balance.Plasma renin activity (PRA) (8,16,23,27) and angiotensin I1 concentration (7) are relatively high in human newborn infants. PRA decreases progressively over weeks and months (8,16,22); a similar trend is followed by aldosterone secretion rates (4), plasma aldosterone (4), and exchangeable sodium (19).The cause of increased activity of the renin-angiotensin system during the neonatal period is not clear. The low sodium intake, the low blood pressure, the hypovolemia, and the increased sympathetic activity ,have been invoked as possible factors. On the other 'hand, no correlation was found between PRA and plasma aldosterone. either in cord blood (10, 26) or in newborn infants . . , aged 2-3 days (26), suggesting that angiotensin I1 is not a predominant regulatory factor controlling aldosterone secretion at this age.In an effort to gain insight into the interplay between renin, sodium, and renal function during the neonatal period, we have studied the relationship between PRA, sodium intake and output, urine osmolality, and glomerular filtration rate (GFR) in hea6hy, full-term newborns of different ~ostnatal aees. In addition. vaso-" pressin was determined in the urine, because limited data are available concerning this hormone in human newborns. 7

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Section: Discussionmentioning

confidence: 99%

“…On the other 'hand, no correlation was found between PRA and plasma aldosterone. either in cord blood (10,26) or in newborn infants . .…”

mentioning

confidence: 99%

Plasma Renin Activity Related to Sodium Balance, Renal Function and Urinary Vasopressin in the Newborn Infant

Godard

Geering

et al. 1979

Pediatr Res

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“…The initial model hypothesized the effects on each dependent variable for 1) age"group; 2) plasma concentration of angiotensin; and 3) a term representing the interaction of plasma concentration of angiotensin and age group. These terms were likewise entered in the model in the above order to provide: 1) an adjustment for variation in overall plasma angiotensin concentrations from age group to age [11][12][13][14][15][16][17][18][19][20] PROCEEDINGS/INTERAMERICAN SOCIETY SUPP II, HYPERTENSION, VOL 3, No 6, NOV/DEC, 1981 group; 2) a test of the main effects of plasma angiotensin concentration; and 3) a final test (homogeneity of slopes) of the possible interaction of plasma angiotensin concentration and age groups.…”

Section: Statisticsmentioning

confidence: 99%

Importance of plasma angiotensin concentrations in a comparative study of responses to angiotensin in the maturing newborn lamb.

Wilson¹,

Kaiser²,

Wright³

et al. 1981

Hypertension

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“…The renin-angiotensin system levels are high in the newborn human (6,13,16), lamb (20), and canine puppy (5). These high renin-angiotensin levels contribute to basal control of blood pressure (19)and possibly decreased pressor responsiveness to angiotensin 11 (18) in the newborn lamb.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Salt Loading on the Renin-Angiotensin Control of Blood Pressure in the Newborn Lamb

Siegel¹

1983

Pediatr Res

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SummaryThe renin-angiotensin system control of newborn blood pressure was studied in six sets of twin newborn lambs. The mean aortic blood pressure and plasma renin activity (PRA) was 79.6 f 0.96 mmHg (mean and S.E.) and 6.88 + 0.83 ng/ml/h in the chronically salt-loaded lambs (10 mEq/kg/day for 5 days); 86.16 + 1.8 mmHg ( P < 0.001) and 20.48 f 2.46 ng/ml/h ( P < 0.001), respectively in the control lambs. PRA and % change after angiotensin 11 blockade with saralasin was greater in the control lambs, 181.5 2 6.09 ng/ml/h and 780% than in the chronically salt-loaded lambs, 40 f 10.47 and 480%, P < 0.001. Blood pressure decreased 10 mmHg only in the control lambs, P < 0.001. An angiotensin 11 dose of 0.25 pg/kg/min increased blood pressure 32 + 3.1 mmHg in control mambs, and 0.10 pg/kg/min increased blood pressure 32 + 3.2 mmHg in acutely salt-loaded (10 mEq/kg in 20 ml 5% dextrose/water) lambs. PRA and mean aortic blood pressure decreased in the acutely salt-loaded lambs from 22.3 + 3.0 ng/ml/ h and86.6 f 1.0mmHg to 11.3 f 1.1 and76.4 f 0.8, P < 0.01, respectively. These data show that sodium loading will suppress the basal renin-angiotensin system levels, and mean aortic blood pressure; decrease the hypotensive and PRA responses to saralasin; and increase the pressor responsiveness to angiotensin 11. Abbreviations D/W, dextrose/water PRA, plasma renin activity Blood pressure is under volume and vasoconstrictive control. In the normal newborn lamb, basal blood pressure is maintained under the vasoconstrictor control of the renin-angiotensin system (19). Pressor responsiveness to angiotensin 11 is decreased compared to the ewe (18). These altered responses may be secondary to the very high renin-angiotensin levels present in the newborn lamb (20).Blood pressure control and the renin-angiotensin system are both affected by sodium (8, 10, 11). The purpose of this study was to determine the effects of acute and chronic salt loading on the renin-angiotensin system and blood pressure control in the newborn lamb. MATERIALS AND METHODSSix sets of twin newborn lambs 7-14 days (7-9 kg) and 14-21 days (11-13 kg) were studied for each experiment. The nursing lambs with their mothers were obtained from the vivarium. Polyvinyl catheters were inserted into the femoral artery and vein under local anesthetic (1% lidocaine). The animals were restrained on a specially constructed board, so that they were nonstressed and warm, and studied 2 days after catheter placement. Experiment 1. NaCl(10 mEq/kg in 20 ml5% D/W) was infused over 60 rnin in one of each set of twin lambs 7-14 days of age.Serial doses of angiotensin 11 (0.025, 0.5, 0.1, and 0.25 yg/kg/ min) were infused for 15 rnin each into the salt-loaded and control lambs. Blood samples for PRA were drawn before and 55 and 60 rnin after the NaCl infusion. Mean aortic blood pressure was monitored continuously.Experiment 2. NaC1 (10 mEq/kg/day in 50 ml 5% D/W) was infused slowly over 2 h for 5 days @to one of each set of twin lambs 14-21 days of age. On the 5th day, two baseline bl...

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The Renin-Angiotensin-Aldosterone System in Mother and Fetus at Term

Cited by 55 publications

References 18 publications

Plasma Renin Activity Related to Sodium Balance, Renal Function and Urinary Vasopressin in the Newborn Infant

Plasma Renin Activity Related to Sodium Balance, Renal Function and Urinary Vasopressin in the Newborn Infant

Importance of plasma angiotensin concentrations in a comparative study of responses to angiotensin in the maturing newborn lamb.

The Effects of Salt Loading on the Renin-Angiotensin Control of Blood Pressure in the Newborn Lamb

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