Fig. 3.
Adenylylyl cyclase function and GLP-1 receptor (R)-mediated response in human islets. Human islets on arrival at National Institute on Aging were cultured with glucose for 1 h (A) or 24 h (B and C), as labeled. At the end of incubation, vehicle, forskolin (10 μM), or exendin (EX)-4 (1 nM) were added to the culture for 30 min, and intracellular cAMP levels were measured. Results are expressed as means ± SE from 3 independent islet preparations. *P < 0.05 and **P < 0.01 vs. corresponding vehicle group; #P < 0.05 vs. 5 mM glucose + EX-4 treatment group.