RESUMO
The experiment was carried out on cultured human stomach glandular carcinoma (SGC-7901 cell line). We previously reported the cytochemical changes of (Na~+-K~+)-ATPase activity and the changes of microvilli. We here studied the relationship among the cAMP, cAMP-PDEase, Mg~(++)-ATPase activity, the cell growth and differentiation. Cells were exposed to Immol/L cAMP together with 1 mmol/L theophylline. We showed cAMP specific fluorescence by immunocytochemical method, Mg~(++)-ATPase and cAMP-PDEase activity by cytochemical methods. We found that cAMP with theophylline not only inhibited the growth of these SGC-7901 cells as shown by our previous result, but also decreased the activity of Mg~(++)-ATPase and 3', 5'-cyclic monophosphate phosphodiesterase. The result indicates that exogenous cAMP can inhibit 3', 5'-cAMP-PDEase and Mg~(++)-ATPase activity and increase cAMP level in cell, and cAMP regulated the growth and differentiation of SGC-7901 cell line
RESUMO
The experiment was carried out on Hepatoma-22 ascitic tumor cells of mice in vivo. Daily injection of 2 mg cAMP with 1 mg theophylline into the peritoneal cavity for 7 and 8 days, then these animals were sacrificed. We found that cAMP with theophylline inhibit the growth of tumor cells of Hepatoma-22 ascitic and decrease the activity of Mg~(++), (Na~+-K~+)-ATPase and cAMP-PDE on the cell surface of H-22 tumor cells of mice by cytochemical electron microscopy. Exogenic cAMP and theophlline decrease the activities of these enzymes and elevate the intracellular content of cAMP. These may indicate the reversion transformation of the cancer cell.