FIG 3.

Induced activinB expression in β-tumor cells leads to a progressive downregulation of insulin expression. (A) Immunohistochemical analysis of activinB expression in βMen1 and control pancreas. Islets are outlined by dashed lines. (B) Quantification of intraislet activinB content. Size-matched hand-picket islets from 9-month-old βMen1 (n = 4) and control (n = 4) animals were used to extract protein and quantify activinB content by ELISA. Data are represented as means ± SEM of triplicate measurements of 4 independent samples per genotype. *, P < 0.05 by the Student t test. (C) Immunofluorescent colocalization of activinB and insulin within 10- and 14-month-old tumor lesions and control islets. Right panels are higher magnifications of dashed areas.