Fig. 6. Uninfected and GFP-transduced pseudo-islets show similar secretion patterns. (A) Pseudo-islets were perfused with glucose concentrations ranging from 2.8 mM to 16.8 mM in the absence or presence of 1 mM IBMX and 5 µM FSK. Infected (open squares) and uninfected (grey squares) pseudo-islets showed a similar secretion pattern: they did not increase insulin release for glucose concentrations <11.2 mM but did significantly increase insulin release in response to 16.8 mM glucose, and released even more insulin when glucose was associated with drugs increasing the intracellular concentration of cAMP. Data are means minus the s.e.m. of three experiments. (B) Total insulin content [ng per 50 pseudo-islets (pi)] was similar in uninfected pseudo-islets (grey columns) and in pseudo-islets infected with lentiviral vectors coding for GFP (open columns). (C) Pseudo-islets expressing GFP (open columns) functioned as uninfected pseudo-islets (grey columns), i.e. they showed increased insulin secretion when the glucose concentration was raised from the basal value of 5.6 mM to the stimulatory concentration of 16.8 mM and even more when 1 mM IBMX plus 5 µM FSK were added to the perfusing medium. Data are means plus s.e.m. of three experiments.