title: [Temporally Relationship between Renal Local Clock System and Circadian Rhythm of the Water Electrolyte Excretion].
abstract: OBJECTIVE
  To investigate the relationship of the circadian rhythm of the urine volume and urine electrolytes excretion rate and the daily expression pattern of the clock genes and clock-controlled genes with the water electrolyte transportation circadian pattern in rat kidneys.
  
  
  METHODS
  Male adult SD rats were exposed to in a light:dark (12:12) cycles. We collected two period urine from zeitgeber time (ZT)00:00-ZT12:00 (light time,rest period) and ZT12:00-24:00 (dark time,activity period) and then compared the urinary excretion rates of volume, sodium, potassium, and chloride at light time with those at dark time. Rats were sacrificed every 4 hours throughout a 24-hour day-night cycle. Circadian clock gene CLOCK, BMAL1,Per1,Per2,Cry1,Cry2 and kidney specific clock-controlled gene NHE3,αENaC、NCC,Ptges,V1aR,V2R expression were profiled by real-time quantitative polymerase chain reaction. Data were analysed by a partial Fourier analysis and a stepwise regression technique.
  
  
  RESULTS
  Urine volume and urine potassium excretion rate displayed high level at dark time and low at light time in SD rats (P<0.05),and urine sodium and chloride excretion rate also showed the trend(P>0.05).Clock gene CLOCK,BMAL1,Per1,Per2,Cry1,Cry2(P<0.05)and kidney specific clock-controlled gene NHE3, αENaC, NCC, Ptges, V1aR, V2R (P<0.05)mRNA expression showed circadian pattern,and the peak times of the genes were in the dark time.
  
  
  CONCLUSIONS
  Urine volume and urine electrolyte excretion rate which displayed circadian pattern were temporally coupled with the rhythm of expression of clock and clock-controlled genes associated with water electrolyte transportation in rats kidney.
authors.affiliation: Department of Nephrology,PUMC Hospital,CAMS and PUMC,Beijing 100730,China.
authors.forename: Rui-Yu
authors.initials: RY
authors.lastname: Zhang
authors.affiliation: Department of Nephrology,PUMC Hospital,CAMS and PUMC,Beijing 100730,China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Mou
authors.affiliation: Department of Nephrology,PUMC Hospital,CAMS and PUMC,Beijing 100730,China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Li
authors.affiliation: Department of Nephrology,PUMC Hospital,CAMS and PUMC,Beijing 100730,China.
authors.forename: Xue-Wang
authors.initials: XW
authors.lastname: Li
authors.affiliation: Department of Nephrology,PUMC Hospital,CAMS and PUMC,Beijing 100730,China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qin
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D004573:Electrolytes; D007668:Kidney; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D014867:Water
chemical_list: D004573:Electrolytes; D014867:Water