of both ~-lipoic acid and DHLA in the cells and in
the culture medium were determined by HPLC with
electrochemical detection at various times up to 2 h.
The intracellular concentration of DHLA in the Jurkat
cells reached 1.5 mM within 10 min. It was also found
that the cells released DHLA into the medium.
The results indicate that normal mammalian cells
are capable of taking up a-lipoic acid, reducing it to
DHLA, and releasing DHLA. Hence, the effects of
both a-lipoic acid and DHLA may be present both
intracellularly and extracellularly when a-lipoic acid
alone is administered extracellularly. This has important
implications in, for example, the use of a-lipoic
acid supplementation to prevent LDL oxidation.