title: Physiologic changes of urinary proteome by caffeine and excessive water intake.
abstract: BACKGROUND
  Diurnal variations and physiologic changes of urinary proteome have been suggested in the urinary proteomics field. However, no clear evidence has been demonstrated. The present study thus aimed to define changes in urinary proteome by physiological stimuli, i.e. caffeine intake and excessive water drinking, both of which cause physiologic diuresis.
  
  
  METHODS
  Urine samples were collected from 30 healthy individuals under three different conditions: (i) morning void as the control; (ii) after drinking a cup of coffee; and (iii) after drinking 1 L of water within 20 min. Thereafter, differentially excreted proteins were analyzed by 2-DE proteomics approach and validated by Western blotting and ELISA.
  
  
  RESULTS
  Spot matching, quantitative intensity analysis, and ANOVA followed by Tukey's post-hoc multiple comparisons and the Bonferroni correction revealed significant differences in levels of five protein spots among three different conditions. These proteins were identified by quadrupole time-of-flight mass spectrometry (Q-TOF MS) and/or MS/MS analyses as kininogen 1 isoform 3, β-actin, prostaglandin D synthase (PGDS), fibrinogen α-chain and immunoglobulin light chain. Among these, the decreased level of immunoglobulin was successfully validated by Western blotting and ELISA.
  
  
  CONCLUSIONS
  These data indicated that caffeine intake and excessive water drinking could affect urinary excretion of some proteins and may affect urinary proteome analysis.
authors.affiliation: .
authors.forename: Paleerath
authors.initials: P
authors.lastname: Peerapen
authors.affiliation: .
authors.forename: Nardtaya
authors.initials: N
authors.lastname: Ausakunpipat
authors.affiliation: .
authors.forename: Suchitra
authors.initials: S
authors.lastname: Sutthimethakorn
authors.affiliation: .
authors.forename: Siripat
authors.initials: S
authors.lastname: Aluksanasuwan
authors.affiliation: .
authors.forename: Arada
authors.initials: A
authors.lastname: Vinaiphat
authors.affiliation: .
authors.forename: Visith
authors.initials: V
authors.lastname: Thongboonkerd
mesh_terms: D000328:Adult; D016477:Artifacts; D002110:Caffeine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004326:Drinking; D005260:Female; D006801:Humans; D008297:Male; D020543:Proteome / Q000187:drug effects*; D013997:Time Factors; D016482:Urinalysis; D014867:Water / Q000494:pharmacology*
chemical_list: D020543:Proteome; D014867:Water; D002110:Caffeine
keywords: actin; caffeine; fibrinogen; immunoglobulin; kinonogen; prostaglandin D synthase