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
Volume410
Issue1
Pagination112-20
Date Published2003 Feb 01
ISSN0003-9861
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
Abstract

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