STATE OF SULFHYDRYL IN SELENITE CATARACT

Selenite 20 .mu.mol/kg body wt was a potent and rapid inducer of cataracts in young rats. The rate at which physiological concentrations of selenite catalyzed the oxidation of glutathione in vitro was studied, and selenite was a strong SH oxidant. To test if selenite had the same effect in vivo, the oxidation state of 5 kinds of lenticular S were measured in suckling rats following a cataractous dose of selenite. The measurements included reduced glutathione (GSH), oxidized glutathione (GSSG), protein-bound glutathione (PSSG), reduced protein SH (PSH) and oxidized protein SH (PSSP). While selenite caused a 44% decrease in lens GSH by 6 days postinjection, there was no concurrent increase in GSSG or PSSG. There was no evidence for increased oxidation of PSH to PSSP. To determine if GSH loss was the cause of the selenite cataracts, normal rats were injected with the glutathione synthesis inhibitor buthionine sulfoximine (BSO). Lens GSH dropped > 96% by 4 days post-BSO injection, but no cataracts formed. Selenite cataract did not appear to be caused by extensive SH oxidation and cannot be attributed exclusively to GSH loss.