Fig. 4. ß-Cell depolarization and MAPK pathway are not involved in Cx36 regulation. INS-1 cells were incubated for 24 hours at 2 mM or 20 mM glucose with or without 20 mM KCl, 10 µM nifedipine, 100 nM PMA and 50 µM PD98059, as indicated. Quantitative assessment (± s.e.m.) of six independent experiments revealed that none of these compounds influence Cx36 regulation by glucose. ^***, P<0.001.