title: [Na+/dicarboxylate cotransporter expression changed with aging in basolateral membrane of the renal tubular epithelial cells].
abstract: OBJECTIVE
  To study the change with aging of Na(+)/dicarboxylate cotransporter (NaDC3) expression in basolateral membrane of epithelial cell in proximal renal tubules in rat and human being.
  
  
  METHODS
  Six groups of 6 Wistar rats at the age of: 1 day, 7 days, 1 month, 3 months, 12 months, and 24 months respectively were killed and their kidneys were taken to be examined immunohistochemically. Samples of kidney from 15 normal human beings, 5 in the group aged 6 - 8, 5 in the group aged 32 - 44, and 5 in the group aged 63 - 65, were examined immunohistochemically. Northern blotting, and Western blotting were used to detect the mRNA and protein expression of NaDC3 in renal tissues from both rats and human beings. The concentrations of citrate in both plasma and urine of the rats were tested.
  
  
  RESULTS
  (1) The concentration of citrate in urine was340 mg/L +/- 144 mg/L in rats at the age of 7 days and declined gradually with aging significantly to the value of 59 mg/L +/- 27 mg/L in the rats aged 24 months (P < 0.05). The concentration of citrate in rat plasma was 85 mg/L +/- 45 mg/L and then declined gradually with aging significantly to the value of 31 mg/L +/- 20 mg/L at the age of 24 months (P < 0.05). (2) The renal expression of both mRNA and protein of NaDC3 increased with aging in rats and human beings (P < 0.01). (3) Located in the basolateral membrane of epithelial cell in the proximal renal tubule, NaDC3 expression began to be detected in rat since at the age of 7 days and then increased gradually in comparison with that at the day 7 (P < 0.01). However, the value of NaDC3 expression at the age of 24 months was not significantly different from that at the age of 12 months (P > 0.05). Similar results were also observed in normal human beings.
  
  
  CONCLUSIONS
  NaDC3 may play a role in the aging process through the metabolic mechanism of citrate, etc.
authors.affiliation: Department of Nephrology, Kidney Center and Key Lab of People's Liberation Army, General Hospital of People's Liberation Army, Beijing 100853, China.
authors.forename: Li-xia
authors.initials: LX
authors.lastname: Peng
authors.forename: Xiang-mei
authors.initials: XM
authors.lastname: Chen
authors.forename: Hang
authors.initials: H
authors.lastname: Liu
authors.forename: Quan
authors.initials: Q
authors.lastname: Hong
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Suo-zhu
authors.initials: SZ
authors.lastname: Shi
authors.forename: Xue-guang
authors.initials: XG
authors.lastname: Zhang
authors.forename: Xue-yuan
authors.initials: XY
authors.lastname: Bai
authors.forename: Han-yu
authors.initials: HY
authors.lastname: Zhu
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002648:Child; D029382:Dicarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D029363:Organic Anion Transporters, Sodium-Dependent / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D027981:Symporters / Q000378:metabolism*
chemical_list: D029382:Dicarboxylic Acid Transporters; D008565:Membrane Proteins; D029363:Organic Anion Transporters, Sodium-Dependent; D027981:Symporters