[Flow cytometric analysis of the effect of cAMP on the cell cycle of the 9 L rat glioma in vitro].

Perturbed cell kinetics in 9 L rat brain tumor treated with dibutyryl cyclic AMP (DBcAMP) and theophylline were studied. The methods include a procedure for simultaneous flow cytometric measurements of cellular DNA and amount of bromodeoxyuridine (BrdU) incorporated into cellular DNA and a procedure for flow cytometric measurements of cellular DNA and RNA. Propidium iodide and monoclonal antibody against BrdU were used as a fluorescent probe for total cellular DNA and for BrdU incorporated into cellular DNA, respectively. For analysis of cellular DNA and RNA, acridine orange staining was also applied. The results were as following; cells in S and G2 phase at the time of drug administration (1 mM, each) can undergo mitosis even though a considerable prolongation of G2 phase was apparent. However, cells in G1 at the time of drug administration were arrested in that phase, whereas those cells in S or G2 were able to complete one mitosis before becoming arrest in the G1 phase. These results have been inferred from the study by autographic method with 3H-thymidine. However, using these new methods, these were clearly demonstrated and furthermore, flow cytometric analysis with acridine orange revealed that DBcAMP induced 9 L cells into resting position (G0 cells).