The effect of arginine vasotocin on the isolated amniotic membrane of the guinea pig

Vizsolyi, E.; Perks, A. M.

doi:10.1139/z74-045

Cited by 22 publications

(7 citation statements)

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“…AVT may change fetal/placental blood flow or may have a direct effect on membrane pore size. The latter hypothesis is supported by the report that AVP or AVT decrease osmolar induced water transfer from the fetal to the maternal side of the isolated guinea pig amnion in vitro when AVP or AVT are added to the fetal side of the membranes (8). Effects in this model must be due to membrane flow changes.…”

Section: Discussionmentioning

confidence: 68%

Arginine Vasopressin and Arginine Vasotocin Inhibit Ovine Fetal/Maternal Water Transfer

et al. 1983

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Summarvconcentration of fetal and maternal vascular volume markers.After the infusion of 500 ml 20% mannitol to 12 pregnant ewes, we studied maternal and fetal plasma osmolality and maternal hematocrit responses and monitored blood pressure, heart rate, blood gas, and pH in chronically catheterized fetal lambs at 129-140 days gestation. To examine the effect of arginine vasotocin (AVT) and arginine vasopressin (AVP) on fetal/maternal water transfer, the mannitol infusion was repeated 1 day before or after the baseline mannitol study during a 2-h fetal infusion of AVT (7 pU kg-' min-') or AVP (20-400 pU kg-' emin-') in eight and five animals, respectively. Mannitol was administered to the ewe after 1 h of the 2-h AVT or AVP infusion. The fetal and maternal osmolality and hematocrit responses were compared to the baseline mannitol responses in the same sheep. Maternal and fetal blood gases and pH were measured throughout the study periods during the AVT studies. In four of the ewes, an identical (sham) study was performed substituting 500 ml normal saline for the including hematocrit and osmolality. If an identical osmotic stimulus is repeated during AVP or AVT infusion into the fetal circulation, any effect of the exogenous hormone on placental water flow will be reflected in a diminished or augmented fetal to maternal water flux. Using a modification of the technique developed by Faber and Green (3), we previously infused hypertonic saline into the pregnant ewe as a means of producing a net flux of water from the fetal to the maternal compartment (4). With this model we demonstrated that the acute fetal water loss evokes vigorous fetal AVP secretion. In the present study we employed the model to study the effect of fetal AVP or AVT on placental water flow. We modified the protocol to substitute mannitol (which does not cross the placenta) for the maternal osmolar load and assessed placental water flux before and during the infusion of AVP or AVT to the fetus. mannitol infusion to the ewe. - MATERIALS AND METHODSFetal AVP infusion alone produced a significant decrease in fetal plasma osmolality ( P < 0.001; two-way analysis of variance) and a slight increase in maternal osmolality ( P < 0.05). Fetal AVP or AVT infusion significantly obtunded the fetal osmolality increment induced by maternal mannitol (each P < 0.001); moreover, there was a greater decrease in maternal hematocrit after mannitol alone than after mannitol with AVT (P < 0.05). Fetal hematocrit was maintained unchanged by transfusion with heparinized maternal blood. Maternal and fetal heart rates and maternal blood pressure remained unchanged during the studies. But during the fetal AVT infusion, fetal blood pressure increased from 64 k 3 to 75 k 2 mmHg ( P < 0.01); fetal and maternal Poz and pH remain unchanged; and fetal Pcoz increased from 30 + 2 to 37 + 4 ( P < 0.05). Normal saline (sham protocol) produced no change in any parameter.The data indicate that fetal blood levels of AVP and AVT can influence transplacental water flow. Fetal AVP infusion...

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Section: Discussionmentioning

confidence: 68%

Arginine Vasopressin and Arginine Vasotocin Inhibit Ovine Fetal/Maternal Water Transfer

et al. 1983

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“…Arginine vasopressin has been observed to have an effect on water flow through the guinea pig amnion in vitro. Vizsolyi and Perks [1974] and Manku, Mtabaji and Horrobin [1975] observed that the flow of water from the fetal to the maternal side of the membrane was slow or reversed in the presence of AVP. However, one case report on a woman with hydramnios [Bennebroek Gravenhorst and Wiesenhaan, 1968] indicated that AVP could cause fluid flow out of the amniotic cavity in vivo.…”

Section: Effects Of a Vp On Fetal Urinementioning

confidence: 99%

The Effects of Antidiuretic Hormone on Urine Flow and Composition in the Chronically‐cannulated Ovine Fetus

et al. 1978

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The fetuses of nine pregnant ewes were chronically cannulated between 86 and 130 days with cannulae in one carotid artery, one jugular vein, the fetal bladder and the amniotic cavity. The effects of infused AVP on fetal urine flow rate and composition were studied. A dose of 35 pmol . h-' always caused an increase in urine osmolality and a decrease in flow rate and free water clearance without change in blood pressure. Higher doses (140 pmol.h-1) were significantly pressor and caused increased excretion of sodium, chloride, urea and creatinine. Although this dose always caused an increase in urine osmolality, in five experiments the flow rate also rose. It is concluded that the ovine fetus has the ability to control its own urine flow and composition, and possibly also amniotic fluid volume and composition.Although the compositions of ovine fetal urine and amniotic fluid have been studied by several groups of workers [Alexander, Nixon, Widdas and Wohlzogen 1958;Mellor and Slater, 1972], little is known of the mechanisms which control the volumes and compositions of these fluids. Urine formation begins at about the third month of fetal life in the human [Vernier and Smith, 1968] and by the third trimester is thought to be an important source of amniotic fluid. This view is supported by clinical findings that when urine production is impaired in some way, oligohydramnios often results [Jeffcoate and Scott, 1959]. Thus in studying the maintenance of amniotic fluid volume and composition it becomes relevant to investigate possible controlling factors of fetal renal function.Antidiuretic hormone (ADH) is a hormone which affects renal function in the adult. It has been shown to be present in ovine fetal blood [Alexander, Britton, Forsling, Nixon and Ratcliffe, 1974] but a physiological effect has not yet been demonstrated. In the experiments to be described in this paper a chronic preparation in pregnant sheep was used to study the effects of infused antidiuretic hormone on urine composition and flow rate in the ovine fetus. METHODS Surgery. The fetuses of nine cross-bred merino ewes of known mating dates had vascular, bladder and amniotic cannulae inserted at 86-130 days gestational age (term-147 ± 5 days).

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“…On the basis of these results Pavel [10] postulated that AVT may be mediating the neuroendocrine actions of the pineal gland. The action of AVT on mammalian water metab olism was investigated in vitro by Vizsolyi and Perks [38]. They found that AVT and AVP slow or reverse fetal-maternal water flux across the guinea pig amnion, a finding we have recently reported in vivo [39].…”

Section: Discussionmentioning

confidence: 98%

“…Pavel and co-workers have presented data (already cited) supporting the hypothesis that AVT secreted into CSF might mediate the hypothalamic-pituitary effects of the pineal, including the timing of onset of puberty [10,[34][35][36][37], Roles for CSF AVP and OT have not been fully defined, but there is accumulating evidence that vasopressin improves memory and learning [40]. Possible roles for AVT and AVP in water exchange across the amnion also have been alluded to [38,39], but the significance of OT in amniotic fluid remains obscure.…”

Section: Discussionmentioning

confidence: 99%

Radioimmunoassay of Vasotocin, Vasopressin, and Oxytocin in Human Neonatal Cerebrospinal and Amniotic Fluid

Artman¹,

Leake²,

Weitzman³

et al. 1984

Dev Pharmacol Ther

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Arginine vasotocin (AVT) has been measured in neonatal cerebrospinal fluid (CSF) and human amniotic fluid using a newly developed specific radioimmunoassay system. There were significant amounts of AVT in all samples. Vasopressin and oxytocin also were measured in the samples and could not account for the levels of vasotocin found. The source and function of these neurohypophyseal peptides in CSF and amniotic fluid remains speculative.

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The effect of arginine vasotocin on the isolated amniotic membrane of the guinea pig

Cited by 22 publications

References 0 publications

Arginine Vasopressin and Arginine Vasotocin Inhibit Ovine Fetal/Maternal Water Transfer

Arginine Vasopressin and Arginine Vasotocin Inhibit Ovine Fetal/Maternal Water Transfer

The Effects of Antidiuretic Hormone on Urine Flow and Composition in the Chronically‐cannulated Ovine Fetus

Radioimmunoassay of Vasotocin, Vasopressin, and Oxytocin in Human Neonatal Cerebrospinal and Amniotic Fluid

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