title: Reduced insulin secretion and nocturnal dipping of blood pressure are associated with a disturbed circadian pattern of urine excretion in metabolic syndrome.
abstract: BACKGROUND
  An impaired Na and water excretion rate during daytime is associated with increased cardiovascular risk factors. Recent findings suggest that disturbed circadian rhythms may play an important role in salt-sensitive hypertension and reduced β-cell function.
  
  
  METHODS
  This study investigated clinical implications of the circadian pattern of urine excretion [evaluated as the day to night ratio of urine flow rate (D/N of V)] in 76 patients with metabolic syndrome (MS) not taking diuretics. We analyzed 24-h urinary excretion and blood pressure (BP) during separate day and night periods. In addition nondiabetic patients (n = 46 of 76) underwent an oral glucose tolerance test.
  
  
  RESULTS
  The D/N of V varied largely among subjects (tertile 1 = 1.95 ± 0.40, tertile 3 = 0.67 ± 0.14). In the patients with low D/N of V, systolic BP dipped less at night, independently of age and creatinine clearance (P < 0.01). During the first 60 min of the oral glucose tolerance test, the rise in plasma insulin and the insulinogenic index were positively correlated with the D/N of V, even after adjustment for age, waist circumference, 24-h urine volume, and BP (P < 0.001 for both), suggesting inadequate insulin secretion in poor daytime excretors.
  
  
  CONCLUSIONS
  In patients with MS, a disturbed circadian pattern of urine excretion is associated with a reduced nocturnal dipping of systolic BP and a reduced glucose-induced insulin secretion. These results underline the clinical importance of impaired circadian rhythms in MS and prompt further studies to evaluate the potential of the D/N of V as a prognostic marker in MS patients.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche en Santé 872-E2, Centre de Recherche des Cordeliers, 15 Rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Guerrot
authors.forename: Boris
authors.initials: B
authors.lastname: Hansel
authors.forename: Julie
authors.initials: J
authors.lastname: Perucca
authors.forename: Ronan
authors.initials: R
authors.lastname: Roussel
authors.forename: Nadine
authors.initials: N
authors.lastname: Bouby
authors.forename: Xavier
authors.initials: X
authors.lastname: Girerd
authors.forename: Lise
authors.initials: L
authors.lastname: Bankir
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D024821:Metabolic Syndrome / Q000503:physiopathology* / Q000652:urine*; D008875:Middle Aged
chemical_list: D007328:Insulin