ABSTRACT

Permeability studies continue to provide a wealth of information on cell membrane structure and function. The hydraulic permeability coefficient, Lp, is a measure of the resistance water experiences as it crosses a barrier under the influence of a hydrostatic or osmotic pressure gradient. The diffusional permeability coefficient is a measure of the resistance a solute experiences as it traverses a barrier under the influence of a concentration gradient. The paucity of published data on the permeability properties of mammalian cells other than erythrocytes provided the impetus for the current investigation. The chapter examines the water transport across the Novikoff hepatoma cell membrane. Water transport across the Novikoff cell membrane exhibits the following characteristics: the apparent Ea for osmotic water movement is significantly greater than the Ea for the self-diffusion of water, and osmotic movement of water is directly related to membrane lipid fluidity.