The effect of ethanol and other alcohols on morphometric parameters of rat small intestinal microvillous vesicles.

We have assessed the morphometric parameters of rat small intestinal microvillous vesicles, prepared by a Ca(2+)-precipitation method, from normal, long term ethanol-treated and pair-fed saccharose -treated control rats. The vesicles from normal rats were also directly exposed to ethyl, butyl and benzyl alcohols, respectively. Computerized morphometric analysis was carried out on electron micrographs of microvillous vesicles. The size of vesicles from ethanol-treated rats, as well as control rats, was significantly reduced as compared to normals. Direct exposure of vesicles to alcohols significantly increased vesicle dimensions, with a potency order reflecting the liposolubility of alcohols. These data support the hypothesis that variations in vesicle diameter may be ascribed at least in part to the fluidizing effect of alcohols. Thiamin transport by the vesicles has been measured in the presence of ethanol. The time course of thiamin uptake was not affected by ethanol.