Regulation of cellular retention of paf-acether by extracellular pH and cell concentration.

The role of paf-acether as an intracellular mediator was recently challenged by studies showing that it remained cell-associated in several cell types. We showed that the level of paf-acether found in extracellular medium was strongly reduced when extracellular pH decreased and when cell concentration increased. Therefore the number of cells and extracellular pH should be taken into consideration before speculating on the release vs. retention of paf-acether.