Arginine vasopressin response to hypertonicity in hypertension studied by arginine vasopressin assay in unextracted plasma.
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.


METHODS
Analysis of Posm-PAVP curves observed in individual normotensive and hypertensive subjects rather than 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 osmolality, blood pressure and blood volume was similar in the two groups. Hypertensive subjects showed a tendency towards higher rates of response (pmol AVP/l per mosm per kg) at Posm greater than 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 greater than 290 mosm/kg may reinforce vascular and central nervous pathogenetic mechanisms.
Henneberry
H P
HP
Cobbold Laboratories, Middlesex and University College Medical School, London, UK.
Slater
J D
JD
Eisen
V
V
Führ
S
S
D000328:Adult; D000704:Analysis of Variance; D001127:Arginine Vasopressin / Q000097:blood*; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000453:epidemiology / Q000503:physiopathology; D006982:Hypertonic Solutions; D016018:Least-Squares Analysis; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010953:Plasma Volume; D011863:Radioimmunoassay / Q000379:methods / Q000706:statistics & numerical data; D013997:Time Factors
D006982:Hypertonic Solutions; D001127:Arginine Vasopressin