Involvement of blood glucose in the dimethylthiourea-induced protection against alloxan-induced diabetes.

Dimethylthiourea (DMTU, 4.0 mmol/kg) injected into mice 30 min prior to alloxan injection markedly protected mice against the diabetogenic actions of 75 mg/kg alloxan. At 30 min after the above dose of DMTU alone (no alloxan), there was a marked rise in blood glucose. Mannoheptulose, an antagonist of glucose action at pancreatic beta-cells, when given 24 min after DMTU and 6 min before alloxan, eliminated the DMTU-induced protection. The protection was also removed in the fasted mice in which DMTU did not cause hyperglycemia. These results indicate that DMTU protected mice from alloxan-induced diabetes by the indirect mechanism of producing hyperglycemia at the time of alloxan injection.