Antidiuretic hormone regulation in hemodialysis

The relative influence of stimulation and suppression of osmoreceptors and low and high pressure baroreceptors was studied in 12 patients on hemodialysis. The stimuli were separated by ultrafiltration and dialysis. When high and low baroreceptors were deloaded by volume contraction during ultrafiltration, but there was no change in osmolality, the antidiuretic hormone (ADH) level rose steeply. When osmoreceptors were suppressed, but there was no influence on baroreceptors during dialysis, ADH level declined by the same amount it had increased during ultrafiltration. When osmoreceptors were stimulated by an increase in osmolality in the phase between dialyses, but baroreceptors were loaded by an increase in volume, ADH levels did not change. Others showed that when baroreceptors are stimulated and osmoreceptors suppressed during simultaneous ultrafiltration and dialysis, there is also no change in ADH levels. These results indicate that the hierarchy of receptors regulating ADH is osmoreceptors followed by high and low baroreceptors. Simultaneous stimulation or suppression of both baroreceptors appears equal to the influence by osmoreceptors.