Age-related decline of sodium-dependent ascorbic acid transport in isolated rat hepatocytes

Arch Biochem Biophys. 2003 Feb 1;410(1):112-20. doi: 10.1016/s0003-9861(02)00678-1.


This study investigated whether the age-related decline in hepatic ascorbic acid (AA) levels in rats was due to altered AA uptake. AA concentrations were 68% lower in freshly isolated hepatocytes from old (24-26 months) versus young (3-5 months; p<0.0005) Fischer 344 rats. When incubated with 100 microM AA, cells from old as compared to young rats showed a 66% decline in both the rate of AA transport and the steady state intracellular levels. Sodium-free media significantly reduced AA uptake, suggesting that the sodium-dependent vitamin C transporter (SVCT) was largely responsible for declines in AA transport. Analysis of SVCT messenger RNA (mRNA) levels shows that one isoform of this transport protein, SVCT1, declines 45% with age, with no significant changes in SVCT2 mRNA levels. These results show for the first time that sodium-dependent AA transport declines during the aging process, which may account for much of the loss in tissue AA content.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aging / physiology*
  • Animals
  • Ascorbic Acid / metabolism*
  • Ascorbic Acid / pharmacokinetics
  • Biological Transport / drug effects
  • Chromatography, High Pressure Liquid
  • Dehydroascorbic Acid / metabolism
  • Deoxyglucose / pharmacology
  • Hepatocytes / drug effects
  • Hepatocytes / physiology*
  • Linear Models
  • Male
  • Organic Anion Transporters, Sodium-Dependent / genetics
  • Organic Anion Transporters, Sodium-Dependent / metabolism
  • Rats
  • Rats, Inbred F344
  • Sodium / metabolism*
  • Sodium-Coupled Vitamin C Transporters
  • Symporters / genetics
  • Symporters / metabolism


  • Organic Anion Transporters, Sodium-Dependent
  • Slc23a1 protein, rat
  • Slc23a2 protein, rat
  • Sodium-Coupled Vitamin C Transporters
  • Symporters
  • Deoxyglucose
  • Sodium
  • Ascorbic Acid
  • Dehydroascorbic Acid