Inhibitory effects of horse-anti rat alphafetoprotein (AFP) antibody on cell growth and uptake of sugar for AFP producing rat ascites hepatoma cells in culture

Abstract

Inhibitory effects of horse anti-rat alpha-fetoprotein (AFP) serum (antibody) on uptake of 2-deoxy-Dglucose (DOG) for AFP producing rat ascites hepatoma AH 66 cells were studied.
AH 66 cells cultured in normal Eagle's MEM with 10% calf serum had a 1.5 fold high rate of sugar uptake than AH 66 cells cultured in antibody containing medium. The inhibition of DOG uptake by antibody was dependent on both time and titer of pre-exposured antibody. The rate of DOG uptake in AH 66 cells that were preincubated for 2 hours and 6 hours with antibody prior to the measurement of sugar uptake decreased 70.1% and 58.2%, respectively, lower than that of control cells.
Antibody did not inhibit the phosphorylation of DOG by an intracellular hexokinase.
Kinetic constants for the uptake of DOG in both AH 66 cells treated with antibody and control were calculated from Lineweaver-Burk plots. The Km remained constant at approximately 1.2mM, but the Vmax was 2 fold smaller for antibody treated cells than controled cells (571 and 923n moles12×105 cells/min. for AH 66 cells cultured in antibody containing medium and normal medium, respectively).
Therefore the inhibition of DOG uptake by antibody was suggested the result of adecrease the number of transport site, carrier protein of the sugar, on the surface of the plasma membrane in AH 66 cells.