Effects Of Glucocorticoid Treatment On Beta- And Alpha-Cell Mass In Japanese Adults With And Without Diabetes

The aim of this study was 1) to clarify beta-cell regenerative capacity in the face of glucocorticoid (GC)-induced insulin resistance and 2) to clarify the change in beta- and alpha-cell mass in GC-induced diabetes in humans. We obtained the pancreases from 100 Japanese autopsy case subjects. The case subjects were classified according to whether or not they had received GC therapy before death and the presence or absence of diabetes. Fractional beta-cell area (%BCA) and alpha-cell area (%ACA) were quantified, and the relationship with GC therapy was evaluated. As a result, in case subjects without diabetes, there was no significant difference in %BCA between case subjects with and without GC therapy (1.66 +/- 1.05% vs. 1.21 +/- 0.59%, P = 0.13). %ACA was also not significantly different between the two groups. In case subjects with type 2 diabetes, %BCA and %ACA were both significantly reduced compared with control subjects without diabetes; however, neither %BCA nor %ACA was significantly decreased in case subjects with GC-induced diabetes. There was a significant negative correlation between %BCA and HbA(1c) measured before death; however, this relationship was attenuated in case subjects with GC therapy. In conclusion, the current study suggests that beta- and alpha-cell mass remain largely unchanged in the face of GC-induced insulin resistance in Japanese individuals, implying limited capacity of beta-cell regeneration in adult humans. The absence of apparent beta-cell deficit in case subjects with GC-induced diabetes suggests that GC-induced diabetes is mainly caused by insulin resistance and/or beta-cell dysfunction, but not necessarily a deficit of beta-cell mass.