Abstract | BACKGROUND AND OBJECTIVE: DESIGN:
Vasopressinase was purified from pooled pregnancy serum by ammonium sulphate precipitation, followed by sequential ion exchange, lentil lectin affinity and gel filtration chromatography. Purified enzyme was then used to degrade AVP and the loss of both immunoreactivity and biological activity monitored. Loss of V1 receptor-stimulating activity and V2 receptor-stimulating activity was compared by two-way ANOVA. PATIENTS: Blood was obtained from healthy women between week 34 and the end of pregnancy. Pooled serum from 20-30 patients was used as starting material for the purification of vasopressinase. MEASUREMENTS: AVP immunoreactivity was measured by radioimmunoassay, V1 receptor-stimulating activity by a platelet aggregation bioassay, and V2 receptor-stimulating activity by adenylate cyclase stimulation in LLC-PK1 target cells. RESULTS: Purified vasopressinase was a dimeric protein of molecular weight 330 kDa, which cleaved the synthetic substrate S-benzyl-L-cysteine-4-nitroanilide with a Km of 0.33 mM. Incubation of AVP (0.1 mM) with vasopressinase (0.66 milligrams) at 37 degrees C led to a parallel loss of both AVP immunoreactivity and biological activity. The rates of loss of V1 and V2 receptor mediated activities were not significantly different. CONCLUSIONS: We report the first direct comparison between the loss of V1 and V2 receptor mediated activities of vasopressinase degraded AVP. There was no significant retention of V1, relative to V2, receptor mediated activity. AVP degradation products are unlikely to be pathogenic in hypertensive pregnancy.
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Authors | M P Gordge, D J Williams, N J Huggett, N N Payne, G H Neild |
Journal | Clinical endocrinology
(Clin Endocrinol (Oxf))
Vol. 42
Issue 1
Pg. 51-8
(Jan 1995)
ISSN: 0300-0664 [Print] England |
PMID | 7889632
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Receptors, Vasopressin
- Arginine Vasopressin
- Aminopeptidases
- cysteine aminopeptidase
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Topics |
- Aminopeptidases
(metabolism)
- Arginine Vasopressin
(metabolism)
- Female
- Humans
- Molecular Weight
- Placenta
(enzymology)
- Pre-Eclampsia
(etiology)
- Pregnancy
(blood)
- Receptors, Vasopressin
(metabolism)
- Substrate Specificity
- Time Factors
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