Response of plasma vasopressin to changes in extracellular volume and/or plasma osmolality in XXXX on maintenance hemodialysis.

@entity1 @entity1831 @entity5463 @entity177 @entity2507 @entity551
The effect of changes in extracellular volume versus changes in plasma osmolality on @entity5463 ( @entity1831 ) release was studied in 6 @entity1 with @entity177 maintained on chronic hemodialysis. The day of the study, the @entity1 were treated by sequential ultrafiltration lasting 1 hour followed by a 3-hour conventional hemodialysis session. The ultrafiltration resulted in the removal of 460 to 1,170 ml (mean = 860 ml) of volume. Body weight during the combined procedures fell by 1.6 +/- 0.4 kg (mean +/- s.e.m.) while mean arterial pressure decreased only slightly. Plasma osmolality was unaffected by sequential ultrafiltration, but decreased from 313 +/- 4 mosm/kg @entity2507 to 291 +/- 4 mosm/kg @entity2507 during hemodialysis. Initial plasma @entity1831 concentration was high at 4.45 +/- 0.25 pg/ml and remained unchanged during the sequential ultrafiltration at 4.55 +/- 0.37 pg/ml, but it fell during the hemodialysis to 2.47 +/- 0.45 pg/ml. A @entity551 episode observed in one @entity1 towards the end of hemodialysis resulted in a sharp increase in plasma @entity1831 concentration from 5.5 to 18 pg/ml. During the combined procedures, plasma @entity1831 and plasma osmolality showed a close and linear correlation (r = 0.63, n = 23, p less than 0.001). These findings suggest that in @entity1 on maintenance hemodialysis, changes in plasma osmolality play a predominant role in determining @entity1831 secretion whereas a marked decrease in volume without ensuing @entity551 has no effect on @entity1831 release.
