Figure 3. Islet cell composition is altered in IRE1α^β−/− mice during the hyperglycemic phase.

(A and B) Representative immunofluorescence images for insulin and glucagon expression at indicated time points.

(C) Representative immunofluorescence images for insulin and somatostatin expression at 5 weeks of age.

(D and E) Representative immunofluorescence images for insulin and glucagon expression at indicated time points.

(F) Representative immunofluorescence images showing insulin and somatostatin expression at 24 weeks of age.

(G and H) Quantification of α, β, and δ-cells as a percentage of total islet area at 5 and 24 weeks of age (15–25 islets/animal/time point).

(I) Representative image of an insulin⁺ and glucagon⁺ bihormonal cell in an islet of IRE1α^β−/− mice. Arrow indicates the bihormonal cell.

(J) Representative image of a pancreatic section from 5-week-old IRE1α^β−/− mice showing the presence of single β-cells and small islet clusters. The arrow points to a small islet cluster.

(K and L) The quantification of islet area of 4 weeks and 12 weeks of age IRE1α^fl/fl (n = 3 per time point) and IRE1α^β−/− (4 weeks: n = 3; 12 weeks: n = 4) mice.

All data are represented as mean ± SEM, with statistical analysis performed by Student’s t test (****P < 0.0001, **P < 0.01, *P < 0.05). w: weeks.