The effect of adenosine-3':5'-cyclic monophosphate on the mitotic rate in regenerating Dugesia dorotocephala.

Regenerating posterior sections of the flatworm, Dugesia dorotocephala, were treated with varying concentrations of 5'-adenosine monophosphate (AMP), cyclic AMP (cAMP) and dibutyryl cyclic AMP (Bt2cAMP) for 24 h. M/2000 colchicine was added to the medium during the final 4 h of treatment to collect mitotic figures. The mitotic rate was significantly increased at 0.5, 0.1 and 0.01 mM concentrations of Bt2-cAMP. While Bt2cAMP and cAMP produced comparable results at 0.01 mM, only the Bt2-cAMP-treated organisms exhibited a significantly higher mitotic rate at the 0.1 mM concentration. Theophylline and sodium butyrate did not evoke any stimulatory effect on mitotic rate.