The Dynamics of Vasopressin Release and Blood Volume Regulation During Fetal Hemorrhage in the Lamb Fetus

Robillard, J; Weitzman, Richard E.; Fisher, Delbert A.; Smith, F.

doi:10.1203/00006450-197905000-00006

Cited by 85 publications

(33 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…AVP appears to playa physiological role in the prevention of hemorrhagic hypotension. In previously reported studies on the hemodynamic importance of AVP, its blood pressure-elevating effects have been most apparent following hemorrhage and followigbaroreceptor denervation (4,7,8,12,17). The results of the present study imply that AVP is of even greater importance in the prevention of hemorrhagic hypotension in young than in adult rats.…”

supporting

confidence: 58%

“…The capacity to release AVP was at least as good in young as in adult rats. Previous studies on fetal lambs have shown that the capacity to release AVP in response to blood volume contraction is well developed even in fetal life (12). The AVP levels recorded under basal conditions were high in both the adult and the infant 01 rats; they were 21 and 45 pg-ml", respectively.…”

mentioning

confidence: 71%

“…It is also well documented that the response to the antidiuretic effect is not fully developed at birth (12,13). Newborn infants given high doses of DDAVP intranasally continue to produce an almost isotonic urine (15).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Role of Arginine Vasopressin in Blood Pressure Control in Young Rats

1984

View full text Add to dashboard Cite

SummaryWe investigated the importance of arginine-vasopressin (AVP) for blood pressure control in young and adult rats. Most of the studies were performed on Brattleboro rats with complete diabetes insipidus (DI). In some protocols, Sprague-Dawley rats (SD) were also used. The rats were age 20-24 days (young) or 50-80 days (adult). Adult DI rats have a significantly higher mean arterial pressure (MAP) than adult SD rats. The studies were performed during normovolemia and hypovolemia. Hypovolemia was created by the rapid withdrawal of blood, 0.5-1.5% of body weight. Following bleeding 0.5% of the body weight, young DI rats had a significantly larger decrease in MAP than adult DI and young and adult SD rats. Continuous infusion of AVP (2000 pg ·100 g-l min-I) blunted the hemorrhagic hypotension in the DI rats.In all groups of rats studied, AVP had little effect on the MAP during normovolemia. The effect of AVP (given in a bolus dose of20 or 2000 pg.l00 g-l) on the MAP was in DI rats significantly related to the MAP immediately prior to the AVP administration. No effect on MAP was observed when the initial MAP was 105-112 mm in the young DI rats and 148-157 mmin the adult DI rats. The effect of AVP (20 pg·100 g-l) appeared to be submaximal to maximal. In anaesthetized SD rats, the basal AVP production was higher in the young than in the adult animals. Following bleeding, serum AVP increased in both young and adult rats but the increase was significant only in the adult rats.Abbreviations AVP, arginine vasopressin DI, diabetes insipidus BW, body weight SD, Sprague-Dawley MAP, mean arterial pressure Several investigators have reported that the serum levels of AVP are high in the perinatal period (9, 10). Pohjavuori and Fyhrquist (9) found that the AVP levels in serum from cord blood could be 100 times higher than in serum from the mother.It is generally recognized that AVP may have both an antidiuretic (14) and a hemodynamic effect (3,6,10). It is also well documented that the response to the antidiuretic effect is not fully developed at birth (12, 13). Newborn infants given high doses of DDAVP intranasally continue to produce an almost isotonic urine (15). Studies on isolated collecting tubules from rabbits have shown that the maximal increase in cAMP following exposure to AVP is significantly less in immature than in mature collecting tubules (13). Pohjavuori and Fyhrquist (9) therefore suggested that the high AVP production in the perinatal period was of importance primarily for blood pressure control.The vascular effects of AVP are less well investigated than the antidiuretic effects. The doses of AVP generally required to elicit significant changes in blood pressure are often 100 to 1000 times higher than the doses required to produce antidiuretic effects. The fact that hemorrhage is a potent stimulus for AVP release (4, 5) suggests that AVP is important for the prevention of hemorrhagic hypotension.The aim of this study was to evaluate the role of AVP for blood pressure control in hemorrhagic hypotension in y...

show abstract

supporting

confidence: 58%

mentioning

confidence: 71%

See 1 more Smart Citation

Role of Arginine Vasopressin in Blood Pressure Control in Young Rats

1984

View full text Add to dashboard Cite

show abstract

“…1) is probably due to increased water reabsorption from the distal parts ofthe nephron consequent upon an increase in fetal vasopressin levels. The fetus can produce vasopressin (Rurak, 1979) and the fetal kidney responds to infusions of vasopressin (Robillard, Weitzman, Fisher & Smith, 1979;Lingwood, Hardy, Horacek, McPhee, Scoggins & Wintour, 1978). This increase in water reabsorption occurred only following i.v.…”

mentioning

confidence: 99%

Changes in fetal renal function in response to infusions of a hyperosmotic solution of mannitol to the ewe.

Lumbers¹,

Stevens²

1983

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. In six pregnant ewes a reduction in transplacental water transfer was produced by increasing maternal osmolality (by infusion of 180 g of mannitol in 500 ml of 0-15 M-sodium chloride) and the fetal renal responses to this reduction in water transfer were studied. These responses were compared with the renal responses of five other chronically catheterized fetal lambs whose mothers received I.v. infusions of 500 ml of 0-15 M-sodium chloride.2. Intravenous infusion of 500 ml of 0-15 M-sodium chloride to the ewe produced no changes in fetal plasma sodium, potassium or plasma renin activity and had no effect on fetal renal function.3. After i.v. infusion of mannitol to the ewe, fetal urinary flow rate fell from control levels of 0-69 + 0-12 ml/min to 0-32 + 0 04 ml/min (S.E. of mean, P < 0 006). This fall in urinary flow rate was due to increased water reabsorption because there was no change in glomerular filtration rate and osmolar clearance.4. Fetal urinary sodium excretion increased from 16-2 + 2-0 /imol/min, to 34-2 + 6-,9 ,mol/min (S.E. of mean, P < 0 04). This increase in fetal urinary sodium excretion was due to a fall in the fractional reabsorption of sodium which was related to the rise in fetal plasma sodium levels that occurred following infusion of mannitol to the ewe. The increases in fetal plasma sodium levels were also associated with reductions in fetal plasma renin activity.5. It is concluded that the fetal lamb is capable of limiting renal water excretion and modifying renal sodium excretion in order to maintain the volume and composition of its body fluids.

show abstract

“…(1). In adults of several species, hypotension is known to stimulate several vasoactive systems which act to restore blood pressure towards normal values (2)(3)(4)(5)(6)(7)(8).…”

mentioning

confidence: 99%

Plasma Vasopressin, Renin, and Catecholamines during Nitroprusside-Induced Maternal and Fetal Hypotension in Sheep

et al. 1988

View full text Add to dashboard Cite

ABSTRACT. The release of vasopressin, renin, and catecholamines by the fetus during either maternal or fetal hypotension was examined in chronically catheterized fetal lambs. Nitroprusside was infused intravenously for 1 h into seven pregnant ewes (maternal hypotension) or nine fetal lambs (fetal hypotension); the rates were adjusted to achieve a 15 to 30% decrease in mean blood pressure. During maternal hypotension, mean f S E vasopressin in maternal plasma increased from 1.2 f 0.2 pg.ml-' to 208 f 153 pg.ml-' and plasma renin activity increased from 1.5 f 0.3 ng.ml-'. h-' to 6.6 f 1.6 ng.ml-'. h-'. Fetal vasopressin and plasma renin activity also increased during the same interval from 1.1 f 0.3 to 16.9 +. 7.5 pg.ml-' and 3.7 f 1.1 to 10.5 f 2.85 ng.ml-'.h-', respectively; but no changes were observed in fetal blood pressure, heart rate, or acid base status. During fetal hypotension, mean vasopressin in fetal plasma increased from 4.3 f 3.4 pg. ml-' to 1054 f 772 pg.ml-', plasma renin activity increased from 5.7 f 2.2 ng . ml-' to 22.2 f 7.1 n g ml-' . h-', and total catecholamines from 174 f 58 pg . ml-' to 810 f 416 p g ml-'. There was no change in fetal heart rate, acid base status, osmolality, or sodium concentration. The fetus became and remained hypertensive for at least 1 h after the end of infusion. This prolonged hypertension was associated with elevated levels of vasopressin and plasma renin activity. Peak vasopressin levels were proportional to the total nitroprusside dose in both the ewe and fetus (maternal r = 0.796, fetus r = 0.870). These experiments indicate that as in the adult, vasopressin and the reninangiotensin system in the fetus are stimulated by euvolemic hypotension and may play an important role in the maintenance of fetal blood pressure during an hypotensive challenge. We speculate that the prolonged rebound hypertension represents immaturity of the fetus to fine tune the regulation, release, or metabolism of vasoactive mediators. More likely, the hypertension and elevated hormone levels represent homeostatic mechanisms to combat the nitroprusside-induced diminished cardiac output. Lastly, fetal release of vasopressin, renin-angiotensin, and norepinephrine during maternal hypotension suggests that they are sensitive indicators of early fetal compromise. 7The fetus may be compromised by episodes of maternal hypotension (postural changes, regional anesthesia, placenta previa, etc.) or fetal hypotension (cord occlusion, fetal blood loss secondary to abruptio placentae, etc.) (1). In adults of several species, hypotension is known to stimulate several vasoactive systems which act to restore blood pressure towards normal values (2-8).The ability of the fetus to similarly withstand hypotension may have a significant influence on subsequent short-term and longterm outcome. The present studies were undertaken to determine the fetal response to both maternal and fetal hypotension with respect to fetal release of vasopressin, renin, and catecholamines in the maintenance of fetal blood pressur...

show abstract

The Dynamics of Vasopressin Release and Blood Volume Regulation During Fetal Hemorrhage in the Lamb Fetus

Cited by 85 publications

References 32 publications

Role of Arginine Vasopressin in Blood Pressure Control in Young Rats

Role of Arginine Vasopressin in Blood Pressure Control in Young Rats

Changes in fetal renal function in response to infusions of a hyperosmotic solution of mannitol to the ewe.

Plasma Vasopressin, Renin, and Catecholamines during Nitroprusside-Induced Maternal and Fetal Hypotension in Sheep

Contact Info

Product

Resources

About