Thymidine transport in phytohaemagglutinin-stimulated pig lymphocytes.
Thymidine and uridine transporters in peripheral pig lymphocytes have structural features in common, but are not identical. Accelerated entry of [3H]thymidine begins 12h after the addition of phytohaemagglutinin. The increased thymidine uptake into the cells is characterized by an increase in Vmax. Without alteration of the apparent Km(0.6+/-0.08muM). Thymidine kinase activity is increased 12h after stimulation. Both the increased thymidine uptake and the increased thymidine kinase activity are inhibited in cultures incubated with puromycin: rates of degradation of the two systems are unchanged after phytohaemagglutinin addition, and indicate similar half-lives of about 2h. Thymidine kinase is rate-limiting for thymidine entry up to 18h after phytohaemagglutinin addition; increase in its synthesis is detectable about 6h before net incorporation of thymidine into DNA is significantly promoted.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D007700:Kinetics; D037102:Lectins / Q000494:pharmacology*; D008214:Lymphocytes / Q000201:enzymology / Q000378:metabolism*; D011691:Puromycin / Q000378:metabolism; D013552:Swine; D013936:Thymidine / Q000378:metabolism*; D013937:Thymidine Kinase / Q000378:metabolism; D014529:Uridine / Q000378:metabolism
D037102:Lectins; D011691:Puromycin; D004247:DNA; D013937:Thymidine Kinase; D013936:Thymidine; D014529:Uridine