Toxin-induced IDDM (insulin dependent diabetes mellitus) in the musk shrew

We administered streptozotocin (STZ) and alloxan (AL) to the musk shrew (Suncus murinus, Insectivora) to determine the effective diabetogenic dose of the two toxins for this species. A single intraperitoneal (i.p.) injection of 75 mg/kgBW or the consecutive 5-day s injection of 25 mg/kgBW of STZ to non-fasted shrews, effectively (100%) induced hyperglycemia (> or = 300 mg/dl) with hypoinsulinaemia (< 30% of control level) in male shrews at 10 days after administration. Morphological studies showed cytological changes of B cells in the pancreatic islets of diabetic shrews. Hyperglycemic shrews induced by STZ were thus in IDDM (insulin dependent diabetes mellitus), and showed high susceptibility to the diabetogenic effect of STZ as compared with rodents. Shrews showed a sex difference in the diabetogenic susceptibility to STZ as do mice (male > female). They also showed a species specific resistance to the diabetogenic effect of AL. Of the eight shrews (with 8-hr fasting) that has been treated with a single injection of 200 mg/kgBW of AL, seven (88%) survived at least 10 days, showing no signs of hyperglycemia. All shrews died within 3 day s after injection of 250 or 300 mg/kgBW. These results indicated that the STZ-induced diabetic shrew is a unique animal model and may be useful for IDDM research. On the other hand, the musk shrew was highly resistant to the diabetogenic effects of AL.