title: Decrease in nocturnal urinary levels of arginine vasopressin in patients with nocturnal polyuria.
abstract: OBJECTIVE
  To elucidate whether heart function and endocrine levels of arginine vasopressin (AVP) or solute diuresis is associated with the nocturnal voided volume, and whether the urinary AVP could be a parameter for screening for nocturnal polyuria caused by AVP insufficiency.
  
  
  METHODS
  A total of 50 patients were enrolled in this study. The blood and urine samples were obtained every 6 hours at 6 pm, 12 am, 6 am, and 12 pm. Atrial natriuretic peptide and brain natriuretic peptide were measured at admission. All voided urine samples were collected every 6 hours for examination. The evaluation items were AVP, osmolarity, sodium, potassium, chloride, and creatinine in blood and urine.
  
  
  RESULTS
  The patients were classified into a group with nocturnal polyuria (n = 21) and a group without nocturnal polyuria (n = 25). There was no significant difference in atrial natriuretic peptide, brain natriuretic peptide, electrolytes in blood and urine, and plasma AVP of each sample between the two groups, but urinary AVP/urinary creatinine and urine osmolarity at 12 am and 6 am in the group with nocturnal polyuria were significantly lower than those in the group without nocturnal polyuria. The nocturnal voided volume correlated with urinary AVP/urinary creatinine level in the urine samples obtained at 12 am and 6 am.
  
  
  CONCLUSIONS
  The present data have demonstrated that the significant decrease in urinary AVP/urinary creatinine level at 6 am may contribute to the increased nocturnal voided volume followed by nocturia and that the circadian rhythm disorder of AVP can be predicted by a noninvasive test measuring urinary AVP/urinary creatinine in the urine voided early in the morning.
authors.affiliation: Department of Urology, Nara Medical University, Kasihara, Nara, Japan. hirayamn@nmu-gw.naramed-u.ac.jp
authors.forename: Akihide
authors.initials: A
authors.lastname: Hirayama
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Akiyama
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hirao
mesh_terms: D000368:Aged; D001127:Arginine Vasopressin / Q000652:urine*; D002940:Circadian Rhythm; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D045265:Natriuretic Peptides / Q000652:urine; D009994:Osmolar Concentration; D011141:Polyuria / Q000150:complications / Q000652:urine*; D014555:Urination Disorders / Q000209:etiology / Q000652:urine*
chemical_list: D045265:Natriuretic Peptides; D001127:Arginine Vasopressin; D003404:Creatinine