TitleAge-related decline of sodium-dependent ascorbic acid transport in isolated rat hepatocytes.
Publication TypeJournal Article
Year of Publication2003
AuthorsMichels AJ, Joisher N, Hagen TM
JournalArch Biochem Biophys
Date Published2003 Feb 01
KeywordsAging, Animals, Ascorbic Acid, Biological Transport, Chromatography, High Pressure Liquid, Dehydroascorbic Acid, Deoxyglucose, Hepatocytes, Linear Models, Male, Organic Anion Transporters, Sodium-Dependent, Rats, Rats, Inbred F344, Sodium, Sodium-Coupled Vitamin C Transporters, Symporters

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.

Alternate JournalArch. Biochem. Biophys.
PubMed ID12559983
Grant ListAG17141 / AG / NIA NIH HHS / United States