[3H]-2-DG uptake (GU) in L6 myotubes was increased (a) by insulin (10 μM) (Student's t-test, P<0.01, n=6) or zinterol (100 nM) (P<0.05, n=6), as well as (b) by the direct Gs activator, cholera toxin (ChT, 1 μg ml−1) (P<0.01, n=3) and the cell-permeable cAMP analogues, 8-Br-cAMP (1 mM) (P<0.01, n=4) or dbcAMP (1 mM) (P<0.05, n=4). In (c) the adenylate cyclase inhibitor, ddA (50 μM) partially inhibited GU stimulated by zinterol (P=0.02, n=6), but had no significant effect on either basal (P=0.79, n=5) or insulin (1 μM)-stimulated GU (P=0.59, n=2). In (d and e) cAMP levels in response to zinterol (100 nM) or forskolin (10 μM) were significantly inhibited by ddA (P<0.05, n=3–5).