Arginine vasopressin response to hypertonicity in hypertension studied by arginine vasopressin assay in unextracted plasma
Henneberry, H.P.; Slater, J.D.; Eisen, V.; Führ, S.
Journal of Hypertension 10(3): 221-228
1992
ISSN/ISBN: 0263-6352 PMID: 1315818 Document Number: 396353
Objective: To investigate whether plasma osmolality (Posm)-plasma arginine vasopressin (PAVP) response relationships with particular characteristics of sensitivity, gain or response pattern (linear/non-linear) occur more frequently in hypertensive than normotensive subjects. Design: Analysis of Posm-PAVP curves observed in individual normotensive and hypertensive subjects rather than the whole groups was considered appropriate for the described objective. Methods: A sensitive and precise radioimmunoassay of PAVP in unextracted plasma was developed. Posm was raised in 11 normotensive and 19 hypertensive subjects by infusion of NaCl solution (0.86 mol/l, i.v.), and PAVP assayed at intervals. Best-fitting linear and non-linear equations for the Posm-PAVP relationship were established by computer. Results: The mean rise in osomality, blood pressure and blood volume was similar in the two groups. Hypertensive subjects showed a tendency towards higher rates of response (pmol AVP/I per mosm per kg) at Posm > 290 mosm/kg, leading to a non-linear response pattern compared with the normotensive subjects. Conclusions: The enhanced PAVP responses found in the hypertensive subjects at Posm > 290 mosm/kg may reinfoce vascular and central nervous pathogenetic mechanisms.