[The Na,K-ATPase pump and blast transformation of human peripheral blood lymphocytes].

A transition of phytohemagglutinin (PHA)-activated human lymphocytes from resting state to proliferation is accompanied by an early and a long-term, delayed increase in ouabain-sensitive Rb influx. The long-term (between 16 and 48 h of PHA action) activation of the Na,K-ATPase pump is concomitant with the enlargement of lymphocytes and precedes the onset of DNA synthesis. When inhibiting the protein synthesis in activated lymphocytes, cycloheximide fails to suppress the early rise in Rb influx; however, it abolishes completely the increase in ouabain-sensitive Rb fluxes after 2 h of PHA stimulation. The inhibitors of transcription, actinomycin D and alpha-amantin, in doses suppressing the increase in the PHA-induced RNA synthesis, do not abolish the elevated Rb influx within 20-24 h of PHA action, and inhibit a growth-related increase in Rb influx during the 2nd day of activation. It is concluded that in mitogen-stimulated human lymphocytes the protein synthesis dependent enhancement of Na,K-ATPase pump activity is different in its nature at different phases of G0/G1/S progression. Unlike the early pump stimulation (0.5-2 h), the late elevation of K influxes associated with the growth of lymphocytes, is due to the regulation of the Na,K-ATPase pump at translational (2-20 h) and transcriptional (after 20 h) levels.