Expression of RegI, RegII and Reg IV protein in the pancreas before and after low-dose STZ treatment. Levels of RegI (A), RegII (C) and Reg IV (E) expression in the islets isolated from young and old mice by Western blot analysis. Analysis of immunoblot of RegI (B), RegII (D) and Reg IV (F) normalized to β-actin. Values were representative of islets from 4–5 mice per group. **p < 0.01 versus old WT mice.