Glutathione is the most abundant and ubiquitous non‾protein thiol in mammalian cells and serves as a primary nucleophile in numerous protective detoxification reactions. The maintenance of GSH homeostasis is dependent upon the interrelationships of each of a number of anabolic and catabolic reactions. In most cells,GSH concentrations are in constant flux, with a series of feedback mechanisms in influencing the steady state leverls of the tripeptide.

Although many cells types can efflux intact GSH, there are few definitive reports of uptake of intact GSH in vivo. In several organ systems, evidence exists to suggest that GSH is not transported intact into cells. In lymphoid and kidney cells, GSH can initially be effluxed from the cell, broken down into its constituent amino acids and transported back into the cell leading to increased de novo synthesis. Extracellularly supplied cysteine can be an especially effective stimulus to increasing the intracellular synthetic rate of GSH. Limitations to this approach include the fact that cysteine is itself toxic to cells if supplied at micromolar concentrations.

Since the amino acid composition of Crassostrea gigas extract powder (JCOE) has shown a high level of glutamic acid and taurine, we have asked whether these components present in the JCOE could be a contributory factor in enhancing GSH and GST.

Statistically significant increases in GSH occurred in HL60 cells exposed to increased concentrations of JCOE(0.05% and 0.1%) but no significant change in the effects on GST. Because of the high taurine levels measured in the extract, the effects of micromolar taurine supplementation of the medium was studied.A modest, but not statistically significant increase in both GSH levels and GST activity.　It is concluded therefore that while the taurine present in the JCOE could be a contributory factor in enhancing GSH and GST, it was not the only stimulus. Moreover,JCOE can be used as orally active inducer of GSH-related enzyme systems and its clinical benefit may well be appreciated.