Cycl AMP in Gl-arrested BHK21 cells infected with adenovirus type 12

Changes in intracellular levels of cyclic AMP and activity of adenyl cyclase and cyclic AMP phosphodiesterase were studied in G1-arrested BHK21 cells infected with adenovirus type 12 (Ad12). The intracellular concentration of cyclic AMP is reduced at 8 hours after infection (h.p.i.) and reaches a minimum at 14 h.p.i. The decrease in activity of adenyl cyclase is detected at 7.5 h.p.i.; at 9 h.p.i. the activity is about 50% of that in mock-infected cells. No significant changes were observed in the activity of cyclic AMP phosphodiesterase until 13 h.p.i., thereafter the activity of cyclic AMP phosphodiesterase decreased. It is suggested that the observed changes in cyclic AMP metabolism are related to expression of the viral genome, as the first changes are detected only after appearance of Ad12 mRNA in the infected cells.