ABSTRACT
Cell membranes not only serve in a protective role, as originally suggested, but are also critically involved in many other basic functions. These include uptake of metabolic substrates by cells and the extrusion of waste products, the general maintenance of cell homeostasis, identification of and communication between cells, and the responses to drugs and poisons and to extracellular messengers such as hormones. Underlying these functions is a complex composition and structure that renders membranes directly or indirectly susceptible to many toxic actions. Further, as is discussed here, the toxicokinetic characteristics of nonlipophilic xenobiotics are largely determined by cell membranes. As a result, damage to membrane integrity not only threatens cell composition and volume, and thereby normal function, but also may influence the concentration of toxicants throughout the body.
