The circulating vasopressinase of pregnancy: Species comparison with radioimmunoassay

Rosenbloom, A.A.; Sack, Joseph; Fisher, Delbert A.

doi:10.1016/0002-9378(75)90005-8

Cited by 56 publications

(25 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5). It is noteworthy that although the serum of pregnant woman was found to contain increasingly large amounts of vasopressinase activity as gestation advances, umbilical cord plasma and amniotic fluid have several orders of magnitude less activity (27). Vasopressinase activity, a measure of the degradation of vasopressin, is not detectable in the plasma or amniotic fluid of sheep (27).…”

Section: Discussionmentioning

confidence: 99%

“…It is noteworthy that although the serum of pregnant woman was found to contain increasingly large amounts of vasopressinase activity as gestation advances, umbilical cord plasma and amniotic fluid have several orders of magnitude less activity (27). Vasopressinase activity, a measure of the degradation of vasopressin, is not detectable in the plasma or amniotic fluid of sheep (27). In the absence of intrinsic mechanisms for enzymatic degradation we found that increased concentrations of vasopressin in sheep amniotic fluid persist for at least 24 h; thus, we have data confirming the validity of the measurement of vasopressin as an index of fetal hypoxia in sheep.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Vasopressin Concentration in Amniotic Fluid as an Index of Fetal Hypoxia: Mechanism of Release in Sheep

et al. 1984

View full text Add to dashboard Cite

SummaryHypoxia is a potent stimulus to the release of vasopressin in fetal sheep and, in turn, plasma concentrations of the hormone correlate inversely with fetal oxygenation. Because the fetal kidney contributes to vasopressin clearance, we propose that measurement of increased amounts of vasopressin in amniotic fluid would be indicative of fetal hypoxia. We therefore measured concentrations of vasopressin in amniotic fluid under resting conditions, during and after fetal hypoxia, and with intravenous and intra-amniotic administration of vasopressin in 15 chronically instrumented fetal lambs 111-141 d gestation. In the resting state mean (+SE) vasopressin concentrations in amniotic fluid (1.6 + 0.3 pgml-') did not differ from those in maternal (1.4 f 0.4 p g ml-') or fetal (1.8 f 0.2 pg.ml-') plasma. After exposure of the ewe to 10% Oz or partial occlusion of the umbilical cord, vasopressin concentrations in fetal plasma increased significantly ( P < 0.001) to 200 f 59 pg.ml-' with a delayed increase in amniotic fluid concentrations ( P < 0.03) to 15.8 + 4.5 pg.ml-'.This rise in concentration of vasopressin in amniotic fluid was sustained for at least 24 h and levels at that time were highly correlated with peak plasma concentrations (r = 0.83, P < 0.001).Intravenous infusion of vasopressin into the fetus was accompanied by an equally significant ( P < 0.02) and sustained increase of vasopressin in amniotic fluid. After intraamniotic injection of vasopressin, levels remained increased for at least 24 h.In the third trimester of ovine gestation amniotic fluid vasopressin concentration was a reliable indicator of prior fetal hypoxia. Parallel amounts of antidiuretic activity measured by bioassay and vasopressin by radioimmunoassay confirmed the presence of active hormone in amniotic fluid. Hypoxia alone was not a stimulus to passage of meconium and increased concentrations of vasopressin in fetal plasma were not associated with expulsion of meconium in utero. Despite elevated concentrations of vasopressin in amniotic fluid, no associated changes in intra-uterine pressure were discerned.Evidence from a detailed review of long-term follow-up of infants by Paneth and Stark (19), supports the conclusion that asphyxia as indicated by clinical markers during the process of birth accounts for a smaller proportion of cerebral palsy and severe mental retardation than had been suspected. A major part of this discrepancy could be the result of asphyxia1 episodes occurring before the onset of labor. These episodes may not be reflected in the condition of the infant at birth, but could still lead to severe handicapped conditions. We have therefore endeavored to develop techniques for antipartum fetal surveillance.Data from both clinical and human studies have shown that hypoxic stress is a potent stimulus for the release of vasopressin as well as several other peptide hormones from the fetal pituitary.In the present study we investigated the potential utility of the measurement of vasopressin concentration in the amniotic flu...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Vasopressin Concentration in Amniotic Fluid as an Index of Fetal Hypoxia: Mechanism of Release in Sheep

et al. 1984

View full text Add to dashboard Cite

show abstract

“…Dosages are indicated on the righl. pregnant woman was found to contain increasingly large amounts of vasopressinase activity as gestation advances, umbilical cord plasma and amniotic fluid have several orders of magnitude less activity (27). Vasopressinase activity, a measure of the degradation of vasopressin, is not detectable in the plasma or amniotic fluid of sheep (27).…”

Section: Discussionmentioning

confidence: 99%

“…pregnant woman was found to contain increasingly large amounts of vasopressinase activity as gestation advances, umbilical cord plasma and amniotic fluid have several orders of magnitude less activity (27). Vasopressinase activity, a measure of the degradation of vasopressin, is not detectable in the plasma or amniotic fluid of sheep (27). In the absence of intrinsic mechanisms for enzymatic degradation, we found that increased concentrations of vasopressin in sheep amniotic fluid persist for at least 24 h. Thus, we have data confirming the validity of the measurement of vasopressin as an index of fetal hypoxia in sheep.…”

Section: Discussionmentioning

confidence: 99%

Vasopressin Concentration in Amniotic Fluid as an Index of Fetal Hypoxia: Mechanism of Release in Sheep

et al. 1984

View full text Add to dashboard Cite

“…Most groups have employed 125 1 and the chloramine-T method and have experienced difficulties in obtaining a high specific activity product with some enzymes. For example, it proved difficult to 1:5.000 I:40,000 I:20,000 I:10,000 for plasma angiotensinase: based on RIA of angiotensin I (Strong et al, 1972) for plasma vaspressinase: based on RIA of vasopressin (Rosenbloom et al, 1975) Combine problems of biological assays and of the RIA used for endpoint detection maintain their catalytic activity during isolation procedures, certain others such as the brain isoenzyme of creatine kinase (CK), are partially inactivated during purification (Keutel et al, 1972). This does not necessarily preclude their use as immunogens, though by preference one should always attempt to maintain enzymic activity and thereby guarantee the integrity of the total tertiary structure; as Sela (1969) has pointed out, "antibodies to native proteins are derived mostly against conformational rather than sequential determinants."…”

Section: Categories Of Analytical Techniquesmentioning

confidence: 99%

The Measurement of Enzymes by Radioimmunoassay

1977

View full text Add to dashboard Cite

The circulating vasopressinase of pregnancy: Species comparison with radioimmunoassay

Cited by 56 publications

References 19 publications

Vasopressin Concentration in Amniotic Fluid as an Index of Fetal Hypoxia: Mechanism of Release in Sheep

Vasopressin Concentration in Amniotic Fluid as an Index of Fetal Hypoxia: Mechanism of Release in Sheep

Vasopressin Concentration in Amniotic Fluid as an Index of Fetal Hypoxia: Mechanism of Release in Sheep

The Measurement of Enzymes by Radioimmunoassay

Contact Info

Product

Resources

About