Most previous observations suggest the possibility that sulfhydryl-containing (SH) compunds may play a role in the regulation of carbohydrate metabolism. On the other hand, it is known that alloxan-induced diabetes may be partially prevented by the administration of glutathione and cysteine, which are without effect on streptozotocin (STZ) -induced diabetes. The present investigation was designed to re-examine whether SH-compounds would affect the diabetogenic action of STZ.
Male Wistar rats weighing 200 to 250 gm were used in all experiments. SH-compunds were administered ip or iv 5-30 minutes before an intravenous injection of STZ (65 mg/ kg). There was a tendency to block the development of the STZ-diabetes when cysteine and 2-mercaptopropionyl-glycine were injected ip. The degree of the protective effect, with concomitant elevations of plasma SH content, was markedly enhanced when cysteine (10-1000 mg/kg) was administered iv. Blood SH content was lower in diabetic rats and patients with untreated diabetes mellitus than in controls.
Thus the results of the present study clearly demonstrate that SH-compound could partially prevent the diabetogenic action of STZ. The effect of SH-group appears to be mediated through the common protective mechanism, at least in part, to the attacks of alloxan and STZ on the integrity of the pancreatic beta cell membrane.