[Comparative study of the functional expression of the Na/K-pump in human lymphocytes, activated by phytohemagglutinin, phorbol ester, ionomycin, and interleukin-2].
Rubidium (Rb) influxes via Na/K pump and ouabain-resistant pathways, and protein, RNA and DNA syntheses have been studied in human blood lymphocytes during the cell transit from quiescence to proliferation. In lymphocytes, stimulated either by phytohemagglutinin (PHA), phorbol 12,13-dibutyrate (PDBu) calcium ionophore, ionomycin, or by PDBu and interleukin-2 (IL-2), the late stages of the G0/G1-->S transit are accompanied by sustained 3-fold increased ouabain-sensitive Rb influxes. Using a two-pulse activation by a brief (1 h) PDBu/ionomycin treatment, followed by incubation with PDBu or IL-2 for 48 h, it has been found that both IL-2 and IL-2 receptor (IL-2R) are necessary for a long-term enhancement of Na/K pump. When present at the early stage of PDBu and ionomycin induction, cyclosporin A (CsA, 1 microgram/ml) inhibits the late increase in pump-mediated Rb influxes. However, when applied after the competence induction, CsA produced no effect on the flux increase at the progression stage. It is concluded that in activated human lymphocytes the functional expression of Na/K pump may by associated with IL-2-dependent progression of competent cells in the cell cycle.
Toropova
F V
FV
Institute of Cytology RAS, St. Petersburg.
Vinogradova
T A
TA
Marakhova
I I
II
D002455:Cell Division / Q000187:drug effects; D016572:Cyclosporine / Q000494:pharmacology; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D015759:Ionomycin / Q000494:pharmacology*; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D010835:Phytohemagglutinins / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007376:Interleukin-2; D010835:Phytohemagglutinins; D015240:Phorbol 12,13-Dibutyrate; D015759:Ionomycin; D016572:Cyclosporine; D000254:Sodium-Potassium-Exchanging ATPase