FIGURE 6.

Activation of Rap1 promotes increases in islet cell size and proliferation, the latter through mTORC1. Rat pancreatic islets were isolated and infected with adenoviruses expressing vector or Rap1A-63E the day before the day of the assay and treated with dimethyl sulfoxide (DMSO) alone or rapamycin. A, fixed islet cell nuclei were Hoechst-stained and analyzed by confocal microscopy. The number of nuclei in a defined area was counted using Metamorph software. The data represent the average numbers of nuclei counted from four areas/image slice, with three image slices/islet (n = 4–6 islets/condition). B, islets were incubated with methyl-[³H]thymidine for 24 h before assay. The amount of [³H]thymidine uptake was then determined as measure of cell proliferation. The data represent the means ± S.E. of the average values from three (A) or four (B) independent experiments. *, p > 0.05; ***, p < 0.001 as compared with the indicated condition.