Plasma ADH Levels in Patients Undergoing Chronic Hemodialysis

Abstract

Plasma ADH levels were estimated by radioimmunoassay before and after hemodialysis in 54patients with chronic renal failure. Mean plasma ADH level was 14.4 ± 0.7 (S. E. ) pg/ml before hemodialysis, which was significantly higher than those of normal controls and patients with essential hypertension. After 6 hours of hemodialysis mean plasma ADH level fell significantly to 10.7 ± 1.0 pg/ml despite volume and blood pressure reduction in most cases.
There was significant correlation between plasma ADH levels and effectiv e plasma osmolalities before and after hemodialysis. The regression line shifted to the left and slope was more gentle before hemodialysis in chronic renal failure than in normal controls. After the hemodialysis it still shifted to the left but ran parallel to the regression line of the normal controls. There were no statistically significant correlations between the change in plasma ADH level and the change in blood pressure or blood volume by hemodialysis.
From these results it may be suggested that there occur resetting and alteration of sensitivity of the osmoreceptor and threshold for ADH secretion will be decreased in chronic renal failure. The sensitivity of the osmoreceptor will be improved by hemodialysis.
Impaired degradation of ADH by the diseased kidney a nd other organs and/or alteration of the sensitivity of baroreceptor by the derrangement of the internal milieu might account in part for the increased plasma ADH level in chronic renal failure. The possibility of removal of ADH by hemodialysis was also discussed.