Ca-efflux,from direct membrane injury by CCl4, is elicited by amphiphilic vehicles in vitro

Direct membrane injury by CCl₄, in situations excluding metabolic activation, was evaluated in saponin-permeabilized hepatocytes and in microsomes by measuring immediate Ca²⁺ efflux. A good correlation appears between the Ca²⁺ efflux and the level of CCl₄ in the membrane and also the variations in fluidity. Mixtures of CCl₄ with water-soluble vehicles were used to improve the dispersion of CCl₄ in the medium. The mixtures varied in their ability to elicit the membrane effects of CCl₄. The performance of ethanol and, to a lesser degree, other alcohols, suggests the existence of a water stable structural organization between CCl₄ and these amphiphilic vehicles, facilitating the transfer of CCl₄ to the membrane.