Opposing effects of adenylate cyclase and phospholipase C pathways on DNA synthesis. P6–P7 mouse cells were cultured in the presence of high insulin for 16 hr and treated for 6 hr with 30 μm forskolin (Forsk), vehicle (Con, control; 0.05% DMSO, 0.05% ethanol), phorbol ester PMA (0.2 μm), or inactive enantiomer αPMA. Cultures were pulsed with [³H]dT for the final 2 hr and processed for [³H]dT incorporation. Data are expressed as a percentage of vehicle (9 wells per group). ∗∗∗p < 0.001 versus control.