Alterations in hexose monophosphate shunt during lymphoblastic transformation

This study characterized the alteration in hexose monophosphate shunt (HMPS) activity occurring during lymphoblastic transformation to nonspecific mitogens. Average HMPS activity was threefold higher in phytohemagglutinin (PHA)-stimulated cultures incubated for 68 hr when compared to unstimulated cultures. Serial measurement of HMPS activity indicated that this increased activity was delayed for several hours after the addition of the mitogen and reached a peak of fivefold higher activity during the second day of culture. Glycolysis increased before HMPS activity and was increased during the entire culture period although it was also maximal during the second day of culture. Pokeweed mitogen also resulted in increased glucose metabolism. The increase was of lesser magnitude than PHA and probably reflected the lower degree of lymphoblastic transformation of pokeweed cultures. These studies demonstrate that lymphocytes undergoing blastic transformation have increased HMPS activity which follows a predictable temporal pattern as does glucose consumption. Also, this study demonstrates that the ionization chamber electrometer technique for the direct measurement of 14CO 2 can be applied to the study of long-term tissue cultures.