Objective: To delineate the role of antidiuretic hormone (ADH) in relation to nocturnal polyuria, and to identify the factors influencing on the diurnal antidiuretic hormone level.

Method: The ADH was measured by radioimmuoassay at daytime (2:00 PM) and at nighttime (2:00 AM) with nocturnal polyuria group (11) and without nocturnal polyuria group (8). Urine volume, serum osmolarity, urine osmolarity, and blood pressure were also measured at the same time.

Results: 1) The ADH at 2:00 AM did not increase in nocturnal polyuria group, although it increased in no-symptom group. 2) There was a statistically significant correlation between wheelchair ambulation time and daytime ADH level. 3) The difference of ADH level between daytime and nighttime showed decrease in orthostatic hypotension group.

Conclusion: There was relationship between nocturnal polyuria and diurnal variation of ADH level. The ADH concentration seems to be influenced by the postural factors and sympathetic factors.

Objective: It was reported that nocturnal polyuria in cervical cord injured patients may be due to attenuation of diurnal variation of antidiuretic hormone (ADH) level. However, it has been unclear whether the attenuation of diurnal variation of ADH level caused nocturnal polyuria and bladder overdistension. To improve the management of neurogenic bladder with overdistension during the night, we investigated whether the attenuation of diurnal variation of ADH level is the cause of nocturnal polyuria or bladder overdistens-ion in patients with cervical cord injury.

Method: The subjects consisted of 17 patients with cervical cord injury. The age distribution ranged from 31 to 63 years with an average of 41.5 years. The duration of illness ranged from 5 months to 4 years. Oral intake was restricted below 2,000 ml per day. We measured urine volume and urine osmolarity during the day (8 AM∼8 PM) and night period (8 PM∼8 AM) and the level of plasma ADH and serum osmolarity at 2 PM and 2 AM.

Results: Plasma ADH level was 0.81⁑0.51 pg/ml during the day and 1.04⁑0.65 pg/ml during the night (p=0.17). Urine volume was 1050⁑410 ml during the day and 970⁑550 ml during the night (p=0.92). The average of urine osmolarity was 450.4⁑182.8 mosm during the day and 558.4⁑359 mosm during the night (p=0.25). The average of serum osmolarity was 292.4⁑14.5 mosm during the day and 290.4⁑9.3 mosm during the night (p=0.53).

Conclusion: This study showed that there was no significant difference in each parameter for two periods and urine volume was not increased in spite of attenuation of diurnal variation of ADH level. Therefore this indicated that attenuation of diurnal varia-tion of ADH was less likely responsible for nocturnal polyuria in patients with cervical cord injury.

Objects: To investigate the effect of anti-diuretic hormone (ADH) on nocturnal polyuria in spinal cord injured patients.

Methods: Eleven quadriplegics, seven paraplegics, and nine normal person participated in this study. Quadriplegics and paraplegics ranged from A to C grades according to the ASIA classification. All participants were independent in activities of daily living on wheelchair level. Their intake and output were measured at every 6 hours for 24 hours. The level of ADH was measured by the radioimmunoassay method.

Results: 1) Urine output from midnight to 6:00 A.M. was increased in quadriplegics, but not in paraplegics. 2) ADH at 6:00 A.M. and midnight was decreased in quadriplegics than in controls. No significant change of ADH level was noted in paraplegics. 3) Serum osmolality was higher in quadriplegics than in controls at 6:00 A.M. and midnight.

Conclusion: This study indicates that the nocturnal polynuria in spinal cord injured patient is partly due to a decreased ADH.