Prostaglandins reduce damage by noxious agents to isolated gastric cells. The mechanism remains unexplained. This study was done to examine involvement of microtubules with prostaglandin-mediated cell protection. Cultured mucus-producing cells of rat gastric mucosa were used. Cultured cells were incubated with 16,16-dimethyl-prostaglandin E2 (dmPGE2), colchicine, or vehicle alone in calcium-containing (1.3 mM) and calcium-free medium. The cells were then exposed to 8% ehtanol. Cell integrity and damage were assessed by 51Cr release and in part by transmission electron microscopy (TEM). Specific 51Cr release was closely related to percentage change of necrotic cells assessed by TEM. Cell damage caused by 8% ethanol was greater in medium-containing calcium than in calcium-free medium. dmPGE2 at 10-5M inhibited cell damage in calcium-containing medium. Colchicine itself at concentrations up to 10-5M did not affect cell integrity, but at 10-5M concentration potentiated damage caused by 8% ethanol in calcium-containing medium. Pretreatment with 10-5M colchicine abolished the protective effect of dmPGE2. Microtubules may mediate protection by dmPGE2 of cultured gastric cells against ethanol damage.