E2 action on insulin content, β-cell mass and insulin gene expression.
(A) Insulin content of islets exposed to increasing doses of E2 for 48 hours, V means vehicle, (n = 8, 8 mice), * p<0.05, ** p<0.01, Mann-Whitney test, compared to vehicle. (B) Average size of islets cultured in the presence of vehicle (black column) or 1 nM E2 (white column) for 48 hours. Data represent the mean±SEM of at least 60 islets per condition obtained from 5 different animals. (C) Dispersed islet cells were counted under a fluorescent microscope and results are depicted as a percentage of BrdU-positive cells, values represent the mean±SEM of 4 independent experiments, each representing 3000 cells per condition. (D) Rat pancreatic islets were incubated for up to 6 hours in the presence of 10 nM E2. RNA was subsequently isolated and insulin as well as cyclophilin transcript levels were evaluated by quantitative RT-PCR. Data are presented as fold change of mRNA levels as compared to control untreated islets and normalized to the cyclophilin transcript. Values represent the mean±SEM of 3 independent experiments performed in duplicates. Statistical significance was tested by Student's t test. *, P<0.05; **, P<0.01.