title: Circadian rhythm of urinary potassium excretion in patients with CKD.
abstract: OBJECTIVE
  We previously reported in patients with chronic kidney disease (CKD) that the circadian rhythms of blood pressure (BP) and urinary sodium excretion were both impaired into non-dipper pattern as renal function deteriorated. However, the circadian rhythm of urinary potassium excretion has not been studied in relation to renal dysfunction.
  
  
  METHODS
  BP and urinary excretion rates of sodium (UNaV) and potassium (UKV) were evaluated for daytime and nighttime to estimate their circadian rhythms in 83 subjects with CKD.
  
  
  RESULTS
  As renal function deteriorated, night/day ratios of UNaV and UKV were both increased. Night/day ratio of UKV was positively correlated with night/day ratio of UNaV (r = 0.60, p < 0.0001). Multiple regression analysis (R2 = 0.37, p < 0.0001) revealed that night/day ratio of UKV was determined independently by the night/day ratio of UNaV (r = -0.55, p < 0.0001), rather than renal function or night/day ratio of BP.
  
  
  CONCLUSIONS
  Circadian rhythm of natriuresis was regulated by renal function and night/day ratio of BP. On the other hand, the circadian rhythm of urinary potassium excretion was primarily determined by neither renal function nor BP, but was correlated with that of urinary sodium excretion.
authors.affiliation: Department of Cardio-Renal Medicine and Hypertension, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Miura
authors.forename: Michio
authors.initials: M
authors.lastname: Fukuda
authors.forename: Takehiro
authors.initials: T
authors.lastname: Naito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Togawa
authors.forename: Ryo
authors.initials: R
authors.lastname: Sato
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sasagawa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Tomonari
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kato
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizuno
authors.forename: Minamo
authors.initials: M
authors.lastname: Ono
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shirasawa
authors.forename: Akinori
authors.initials: A
authors.lastname: Ito
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Yoshida
authors.forename: Genjiro
authors.initials: G
authors.lastname: Kimura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D002940:Circadian Rhythm; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009318:Natriuresis; D011188:Potassium / Q000652:urine*; D051436:Renal Insufficiency, Chronic / Q000503:physiopathology* / Q000652:urine; D012964:Sodium / Q000652:urine; D055815:Young Adult
chemical_list: D012964:Sodium; D011188:Potassium