Gene expression of pancreatic glutamic acid decarboxylase in the nonobese diabetic mouse

The 65 kDa isoform of glutamic acid decarboxylase (GAD 65) is an autoantigen implicated in type I diabetes. We have developed a quantitative PCR method to measure GAD 65 mRNA in the pancreas of nonobese diabetic (NOD) mice. Two other nonautoimmune mouse strains were used as controls. In all mice, pancreatic GAD 65 expression declined with age. In 5-week-old NOD mice, a clear difference was detected between males and females. This sexual dimorphism may explain the absence of tolerance to GAD 65 in the NOD female which could contribute to autoimmune destruction of beta cells in the pancreas and subsequent development of diabetes.