Relationship between thirst perception and plasma arginine vasopressin concentration in man

We examined the possibility that measurements of thirst perception in man using the visual Analogue Scale (VAS) can be used to estimate plasma arginine vasopressin concentration in man. In thirty normal subjects (male=15 and female=15), thirst perception (TP, cm) was rated and 5.0ml blood samples were collected for the measurement of plasma arginine vasopressin (P_AVP) using Enzyme Immunoassay kit. Male subjects were statistically significantly older and taller than the females. However, the blood pressures, body weight and body mass index were similar. There was no significant difference, male vs. female in TP (5.26±0.51 vs. 5.39±0.53cm), calculated plasma osmolality from TP, P_osm (298.5±1.7 vs. 299.0±1.8mOsm/kgH₂O) and measured plasma arginine vasopressin, P_AVP (4.85±0.30 vs. 4.71±0.31pg/ml). Furthermore, the calculated P_AVP from TP, P_AVP-TP was similar (5.40±0.69 vs.5.60 ±0.70pg/ml). When P_AVP was calculated from plasma osmolality, P_AVP-P_osm the values were also similar (6.10±0.70 vs. 6.30±0.80pg/ml). There was no statistically significant difference between the measured P_AVP as well as those calculated from TP and from plasma osmolality. It is thus reasonable to conclude that plasma arginine vasopressin concentration maybe estimated using thirst perception and/or plasma osmolality.