Threshold protective effect of glutathione on inorganic mercury inhibition of cerebral sodium pump

Glutathione (GSH) is a sulphydryl tripeptide that protects the oxidation of critical sulphydryl ligands in thiol-containing biological proteins. Consequently, the effect ofGSHon the inhibition of cerebral sodiumpump elicited by inorganic mercury was investigated. We observed that GSH prevented but could not relieve the binding of Hg2+ to sulphydryl groups at the adenosine triphosphate and cationic sites of the electrogenic pump. Furthermore, GSH(= 4mM)markedly inhibited the activity of the pump. SinceGSH is differentially distributed in various organelles (1-15mM), we speculate that there is a probable differential sensitivity of the sodium pump in various organelles towards the antioxidant tripeptide suggesting the possibility of a strong dynamics in the regulation of GSH in the various compartments of the organelles. Taken together, GSH may possibly be a potential candidate as a pre-intervention remedy in cases of mammalian exposure to inorganicmercury.