Temperature dependence and effect of membrane lipid alteration on melphalan transport in L1210 murine leukemia cells.

The transport of melphalan by L1210 lymphoblastic leukemia cells was markedly temperature dependent, and the Arrhenius plot demonstrated a biphasic pattern. Modification of the lipid composition of the cell phospholipids had a significant effect on the transition temperature for melphalan transport even though the K'm and V'max were the same in both types of cells. This shift in transition temperature demonstrates that the discontinuity in the Arrhenius plot was the result of a lipid phase transition and not of an interaction of the two carrier-mediated transport processes. These data indicating differential membrane lipid effects on the transport mechanism provide further evidence of a relationship between lipids and membrane drug transport.