| Phenotype Description |
Mice heterozygous for the Akita spontaneous mutation
(Ins2Akita) are viable and fertile. Symptoms in
heterozygous mutant mice include hyperglycemia,
hypoinsulinemia, polydipsia, and polyuria, beginning around
3-4 weeks of age. The diabetic phenotype is more severe and
progressive in the male than in the female. Obesity or
insulitis does not accompany diabetes. The mean lifespan of
diabetic male mice on the C57BL/NJcl background (305 days)
was significantly shorter than that of nondiabetic males in
another colony of the same strain (690 days). Mortality
rates of diabetic and nondiabetic female mice of this strain
did not differ significantly. Islets from Ins2Akita mice are
depleted of beta cells and those remaining release very
little mature insulin. This, and the finding that mutant
mice respond to exogenously administered insulin, indicate
that Ins2Akita mice will serve as an excellent substitute
for mice made insulin dependent diabetic by treatment with
alloxan or streptozotocin. Heterozygous Ins2Akita mice are
also ideally suited to allogeneic or xenogeneic islet
transplantation protocols because the investigator does not
need to treat the mice with a diabetogen to induce the
hyperglycemic state. Untreated homozygotes rarely survive
beyond 12 weeks of age
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